Gender equity in surgical instruments: ergonomics of ring-handled forceps

INTRODUCTION

Female surgeons have ergonomic issues with commercialized instruments tailored for male surgeons. The purpose of this study was to identify satisfaction levels and ergonomic problems of female surgeons while using laparoscopic forceps with ring-handles and suggest improvement measures.

MATERIAL AND METHODS

A questionnaire was sent to 19,405 members of the Japanese Society of Gastroenterological Surgery via email between 1 August 2022 and 30 September 2022. It included demographic information and specific questions regarding the use of laparoscopic forceps with ring- handles (ergonomic evaluation, influence of the negative aspects of laparoscopic forceps during surgery, physical discomfort in the hands and fingers, degree of satisfaction, and handle size).

RESULTS

Valid responses were received from 1,030 respondents (131 female and 899 male surgeons). The ergonomics of the laparoscopic forceps with ring-handles were rated lower by female surgeons in all ten categories (all p value < 0.05). They also reported a negative impact on surgical manipulation and discomfort to their hands and fingers.

CONCLUSIONS

Female surgeons had a wide variety of ergonomic problems when using laparoscopic forceps with ring-handles, and showed lower levels of satisfaction. Developing a different model tailored to female surgeons with smaller hands and a weaker grip could be a viable solution.

A case of strongly suspected Lynch syndrome with colorectal neuroendocrine carcinoma

Background

Neuroendocrine cell carcinomas (NEC) of the colon and rectum are uncommon, representing ~ 0.1% of all colorectal carcinomas. They are associated with a much worse prognosis compared to adenocarcinoma of the colon and rectum, as death occurs in approximately half of all patients within 1 year. Lynch syndrome (LS) is the most common cause of inherited colorectal cancer, accounting for 2–4% of newly diagnosed colorectal cancer cases. This case is extremely rare which was strongly suspected LS as the background, and NEC as the histological type of colorectal cancer.

Case presentation

The patient was a 44-year-old man presenting with vomiting as the main complaint. He had undergone ileocecal resection for cecal cancer at age 29. The diagnosis was obstructive descending colorectal cancer, and colonoscopy revealed tumors in the rectum and sigmoid colon in addition. Due to multiple occurrences of colorectal cancer and its prevalence in the patient’s family, LS was suspected. The operation which was a subtotal proctocolectomy was performed. Pathological analysis revealed complete curative resection and the descending colon cancer of the obstructed portion was at the most advanced pathological Stage IIIC in UICC TNM classification, and the tissue type was a NEC. The Ki-67 index was 70%. The results of the microsatellite instability (MSI) test showed high-frequency MSI. The BRAF V600E variant was negative. The immunoexpression of MLH1 was positive, MSH2 was negative, PMS2 was positive, and MSH6 was negative.

Conclusions

Extended surgery is recommended for incipient colorectal cancer in LS cases in order to reliably reduce the risk of developing metachronous colorectal cancer. The survival outcome of surgery alone on digestive tract NECs, even locoregional lesions that are completely resection, is extremely poor. It is currently unclear if digestive tract NECs develop more readily in patients with LS. The accumulation of additional cases is necessary.

Comparison of short term surgical outcomes of male and female gastrointestinal surgeons in Japan: retrospective cohort study

OBJECTIVE

To compare short term surgical outcomes between male and female gastrointestinal surgeons in Japan.

DESIGN

Retrospective cohort study.

SETTING

Data from the Japanese National Clinical Database (includes data on >95% of surgeries performed in Japan) (2013-17) and the Japanese Society of Gastroenterological Surgery.

PARTICIPANTS

Male and female surgeons who performed distal gastrectomy, total gastrectomy, and low anterior resection.

MAIN OUTCOME MEASURES

Surgical mortality, surgical mortality combined with postoperative complications, pancreatic fistula (distal gastrectomy/total gastrectomy only), and anastomotic leakage (low anterior resection only). The association of surgeons' gender with surgery related mortality and surgical complications was examined using multivariable logistic regression models adjusted for patient, surgeon, and hospital characteristics.

RESULTS

A total of 149 193 distal gastrectomy surgeries (male surgeons: 140 971 (94.5%); female surgeons: 8222 (5.5%)); 63 417 gastrectomy surgeries (male surgeons: 59 915 (94.5%); female surgeons: 3502 (5.5%)); and 81 593 low anterior resection procedures (male surgeons: 77 864 (95.4%);female surgeons: 3729 (4.6%)) were done. On average, female surgeons had fewer post-registration years, operated on patients at higher risk, and did fewer laparoscopic surgeries than male surgeons. No significant difference was found between male and female surgeons in the adjusted risk for surgical mortality (adjusted odds ratio 0.98 (95% confidence interval 0.74 to 1.29) for distal gastrectomy; 0.83 (0.57 to 1.19) for total gastrectomy; 0.56 (0.30 to 1.05) for low anterior resection), surgical mortality combined with Clavien-Dindo grade ≥3 complications (adjusted odds ratio 1.03 (0.93 to 1.14) for distal gastrectomy; 0.92 (0.81 to 1.05) for total gastrectomy; 1.02 (0.91 to 1.15) for low anterior resection), pancreatic fistula (adjusted odds ratio 1.16 (0.97 to 1.38) for distal gastrectomy; 1.02 (0.84 to 1.23) for total gastrectomy), and anastomotic leakage (adjusted odds ratio 1.04 (0.92 to 1.18) for low anterior resection).

CONCLUSION

This study found no significant adjusted risk difference in the outcomes of surgeries performed by male versus female gastrointestinal surgeons. Despite disadvantages, female surgeons take on patients at high risk. Greater access to surgical training for female physicians is warranted in Japan.

Surgical Experience Disparity Between Male and Female Surgeons in Japan

Question

Does gender disparity exist in the number of surgical experiences among male and female surgeons in Japan?

Findings

In this cross-sectional study covering 1 147 068 total operations in 6 surgical fields performed between 2013 and 2017, surgical experience was classified by surgeons’ gender and years of experience. The number of operations per surgeon was lower for female compared with male surgeons, except in the first 2 years after medical registration; this gender gap widened as the difficulty level of surgery increased.

Meaning

The findings indicate a marked disparity in the surgical experience of female and male surgeons in Japan.

Importance

Women are vastly underrepresented in surgical leadership and management in Japan. The lack of equal opportunities for surgical training is speculated to be the main reason for this disparity; however, this hypothesis has not been investigated thus far.

Objective

To examine gender disparity in the number of surgical experiences among Japanese surgeons.

Design, Setting, and Participants

This retrospective, multicenter cross-sectional study used data from the National Clinical Database, which contains more than 95% of all surgical procedures in Japan. Participants included male and female gastroenterological surgeons who performed appendectomy, cholecystectomy, right hemicolectomy, distal gastrectomy, low anterior resection, and pancreaticoduodenectomy between January 1, 2013, and December 31, 2017.

Exposures

Differences in the number of surgical experiences between male and female surgeons.

Main Outcomes and Measures

The primary outcomes were the total number of operations and number of operations per surgeon by gender and years of experience. Data were analyzed from March 18 to August 31, 2021.

Results

Of 1 147 068 total operations, 83 354 (7.27%) were performed by female surgeons and 1 063 714 (92.73%) by male surgeons. Among the 6 operative procedures, the percentage of operations performed by female surgeons were the highest for appendectomy (n = 20 648 [9.83%]) and cholecystectomy (n = 41 271 [7.89%]) and lowest for low anterior resection (n = 4507 [4.57%]) and pancreaticoduodenectomy (n = 1329 [2.64%]). Regarding the number of operations per surgeon, female surgeons had fewer surgical experiences for all 6 types of operations in all years after registration, except for appendectomy and cholecystectomy in the first 2 years after medical registration. The largest gender disparity for each surgical procedure was 3.17 times more procedures for male vs female surgeons for appendectomy (at 15 years after medical registration), 4.93 times for cholecystectomy (at 30-39 years), 3.65 times for right hemicolectomy (at 30-39 years), 3.02 times for distal gastrectomy (at 27-29 years), 6.75 times for low anterior resection (at 27-29 years), and 22.2 times for pancreaticoduodenectomy (at 30-39 years).

Conclusions and Relevance

This cross-sectional study found that female surgeons had less surgical experience than male surgeons in Japan, and this gap tended to widen with an increase in years of experience, especially for medium- and high-difficulty operations. Gender disparity in surgical experience needs to be eliminated, so that female surgeons can advance to leadership positions.

A "diversity and inclusion" lecture for promoting self-awareness among medical students

PURPOSE

The concept of 'diversity and inclusion' is being adopted worldwide, but it is not yet understood well in Japan. We conducted this study to evaluate the impact of a lecture aimed at increasing awareness of academic careers and the benefits of having diversity and inclusion.

METHODS

Two female surgeons delivered a 120-min lecture on "diversity and inclusion" to third-year medical students at Tokushima University. To assess the impact of the lecture, a questionnaire was distributed, for participants to complete anonymously before and after the lecture.

RESULTS

Eighty-two students participated in the study (39 men, 38 women, and 5 unknown). Based on the questionnaire responses, 57.1% of the students had already perceived inequality in conduct because of gender. A comparison of pre- and post-lecture responses revealed a significant increase in confidence to succeed in their medical career (56.5% vs. 77.5%, p < 0.01). Learners were more likely to believe that gender would not become a barrier to career development (42.4% vs. 66.7%, p < 0.01). Moreover, 90.4% of the students felt positively about a career in surgery following the lecture.

CONCLUSION

The lecture promoted awareness about diversity, self-awareness, and career development and motivated students to consider specializing in surgery later in their career.

Laparoscopic instrument for female surgeons: an innovative model for endoscopic purse-string suture

Commercially available laparoscopic instruments are not designed for female surgeons. We redesigned the endoscopic flexible head purse-string suture instrument for improved use by female surgeons. The weight, total length, and diameter of the swing head handle and clump handle were reduced (786 to 565 g, 715 to 700 mm, 70 to 50 mm, and 30 to 25 mm, respectively). Stroke of the slide for firing and release of the lever was reduced from 92 to 83 mm. This is the first step toward an ergonomic surgical device that considers physical differences related to sex.

Effects of DPP-4 Inhibitors on Blood Glucose Variability in Japanese Patients with Type 2 Diabetes on Maintenance Hemodialysis: A Prospective Observational Exploratory Study

INTRODUCTION

The precise blood glucose (BG) profile of hemodialysis patients is unclear, as is the effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors in hemodialysis patients with type 2 diabetes. Here, we used continuous glucose monitoring (CGM) to evaluate BG variability in these patients and to assess the efficacy of DPP-4 inhibitors, particularly during hemodialysis sessions and at nighttime (UMIN000012638).

METHODS

We examined BG profiles using CGM in 31 maintenance hemodialysis patients with type 2 diabetes. Differences between patients with and without DPP-4 inhibitors (n = 15 and 16, respectively) were analyzed using a linear mixed-effects model to assess changes in glucose levels in 5-min intervals.

RESULTS

The model revealed that DPP-4 inhibitor use was significantly associated with suppression of a rapid drop in glucose levels, both with and without adjustment for BG levels at the start of hemodialysis. Moreover, the model revealed that the two groups differed significantly in the pattern of changes in BG levels from 0:00 to 6:55 am. DPP-4 inhibitors suppressed the tendency for subsequent nocturnal hypoglycemia.

CONCLUSIONS

This prospective observational exploratory study showed that DPP-4 inhibitors could suppress BG variability during hemodialysis sessions as well as subsequent nocturnal changes in patients with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, UMIN000012638.

Transanal total mesorectal excision of giant villous tumor of the lower rectum with McKittrick-Wheelock syndrome: a case report of a novel surgical approach

Background

McKittrick–Wheelock syndrome (MKWS) is caused by a villous tumor of the rectosigmoid colon with hypersecretion of mucus containing electrolytes. Complete resection of the tumor is needed to cure this disease. Transanal total mesorectal excision (TaTME) is currently a promising treatment for lower rectal tumor because of the reliability of its resection margin especially in bulky tumor. We present this first case report of a TaTME for MKWS with a lower rectal tumor.

Case presentation

An 81-year-old woman was admitted to our hospital with diarrhea and acute renal failure. Computed tomography and magnetic resonance imaging examinations revealed an 80-mm-sized enhanced tumor located in her lower rectum without lymph node swelling and distant metastasis. A giant villous tumor secreting mucus was seen in the lower rectum to the anal canal during colonoscopy. The result of tumor biopsy was adenocarcinoma. To preserve the anal function and ensure distal margin, we chose TaTME for curative resection. After improving the electrolyte imbalance, TaTME was performed successfully and R0 resection was achieved. There was no sign of recurrence or electrolyte depletion for 1 year after the surgery.

Conclusion

TaTME could be a promising surgical approach for giant villous tumor with MKWS in the lower rectum.

[A Case of Interstitial Pneumonitis Induced by TAS-102 for Liver and Lung Metastasis of Colorectal Cancer]

A 78-year-old man who developed metastatic liver and lung cancer after undergoing surgery for rectal and sigmoid colon cancer was treated with TAS-102 as fourth-line chemotherapy. He developed high fever and dyspnea and was referred to the emergency room 16 days after receiving the first course of TAS-102. Chest X-ray and computed tomography examinations showed bacterial pneumonia. He was treated with tazobactam/piperacillin, but developed severe dyspnea 4 days later. A diffuse ground-glass appearance was observed in both the lungs on chest X-ray examination, and drug-induced interstitial pneumonitis was suspected. Oxygenation and respiratory support were immediately administered, and steroid pulse therapy with methylprednisolone at 1,000mg/day was initiated. His symptoms and radiographic findings dramatically improved. The TAS102-J003 trial, a double-blind phase 2 trial, showed that interstitial pneumonitis occurs at a rate of only 0.9%, but can lead to severe complications, as observed in the present case. The possibility of interstitial pneumonitis should always be considered when a patient develops a fever and respiratory disorder during treatment containing TAS-102.

[Surgical Resection for Advanced Gastric Cancer with Portal Vein Tumor Embolus - Two Cases]

Gastric cancer with portal tumor embolus is rare and there is no definite strategy for its surgical resection. We report 2 cases ofgastric cancer with portal vein tumor embolus treated using gastrectomy and thrombectomy. Case 1: The patient was a 56- year-old man. We performed total gastrectomy, distal pancreatectomy, splenectomy, and thrombectomy. The patient was treated with 4 courses ofS -1 plus CDDP chemotherapy followed by S-1 administration. Eight months after surgery, CT revealed metastasis in the left adrenal gland and he died 2 years after surgery. Case 2: The patient was a 57-year-old man. We performed total gastrectomy, distal pancreatectomy, splenectomy, partial resection of the transverse colon, and thrombectomy. The patient was treated using adjuvant S-1 chemotherapy followed by UFT administration for 3 years. The patient has been alive with no tumor recurrence for the past 10 years. If there is no other therapeutic option for portal vein embolus, gastrectomy with thrombectomy could increase the possibility oflong -term survival.

[Pathological Complete Response in a Case of Advanced Esophageal Cancer with Widespread Lymph Node Metastases Treated Using Preoperative Chemotherapy with Docetaxel, Cisplatin, and 5-FU(DCF therapy)]

The patient was a 66-year-old woman, who was diagnosed with cT3N3M0, cStage III esophageal cancer with widespread lymph node metastases in the mediastinum and abdomen. She was treated with 2 courses of chemotherapy with docetaxel/ cisplatin/5-FU(DCF therapy). CT and FDG PET-CT showed a significant reduction in both the primary tumor and the metastatic lymph nodes following treatment. We performed subtotal esophagectomy and gastric tube reconstruction with lymphadenectomy. The histopathological findings showed no residual viable tumor cells or foreign body-type giant cells with necrosis. The pathological effect of chemotherapy was defined as Grade 3(pCR). Our case suggested that DCF chemotherapy is potentially a very effective treatment for advanced esophageal cancer with widespread lymph node metastases.

Extracapillary proliferation and arteriolar hyalinosis are associated with long-term kidney survival in IgA nephropathy

BACKGROUND

The Oxford classification of IgA nephropathy consists of four markers as prognosticators. We retrospectively examined the relevance of extracapillary proliferation involving cellular and fibrocellular crescents (Ex) and arteriolar hyalinosis (A) on the long-term outcome of renal function.

METHODS

A total of 314 Japanese patients who were diagnosed with IgA nephropathy, with 12 months or more of follow-up period were included in this study. A total of 186 patients were with UP ≥ 0.5 g/day. Patients with diabetes mellitus or severe kidney injury (eGFR < 30 ml/min/1.73 m(2)) were excluded. The presence of Ex and A were scored 0 in the absence, and 1 in the presence, of each lesion. The end point was determined as a 50 % reduction in initial eGFR or end-stage renal disease defined as eGFR < 15 ml/min/1.73 m(2).

RESULTS

In univariate analyses, the kidney survival rate was significantly lower in patients with Ex1 and A1 if UP ≥ 0.5 g/day. In the patients with UP < 0.5/day, none of the clinical and pathological parameters was determined as a risk factor. In the multivariate model including pathological parameters, Ex1 and A1 were independent risk factors for renal outcome if UP ≥ 0.5 g/day. In those patients treated with RAS-blocker or treated before introduction of methylprednisolone pulse therapy, Ex was the only independent risk factor. In multivariate analysis including clinical parameters, eGFR alone was a risk factor, due to strong correlation with other parameters.

CONCLUSION

Ex and A would be associated with the renal outcome of the patients with UP ≥ 0.5 g/day.

Predicting prolonged hospital stay after laparoscopic cholecystectomy

INTRODUCTION

Widespread application of laparoscopic cholecystectomy (LC) has resulted in a high complication rate and leads to prolonged hospital stays. This study aimed to investigate the preoperative and intraoperative clinical factors that relate to prolongation of hospital stay.

METHODS

We studied 370 patients who underwent LC for gallbladder disease between 2008 and 2012. Clinical risk factors were retrospectively collected. The clinical pathway for LC was indicated for all patients, and they were divided into two groups according to postoperative length of stay (LOS): the normal duration group (LOS ≤5 days) and the long duration (LD) group (LOS ≥6 days). Multiple regression analysis was used to predict risk factors that identified hospital prolongation to create a LOS prediction score.

RESULTS

The normal duration group was 236 patients and the LD group was 134. Seventeen patients (4.6%) required conversion from laparoscopic to open surgery. LOS was 4.82 days in the normal duration group and 12.08 days in the LD group. In the LD group, 18.7% of the patients stayed more than 14 days, but no patients were readmitted. Thirteen clinical factors were statistically different between the two groups. ASA score and LC difficulty were the most predictive risk factors for LOS prolongation. LOS prediction score consisted of eight variables selected from 13 factors; it helped determine the likelihood of whether a patients' hospital stay was prolonged (sensitivity, 82.1%; specificity, 75.0%).

CONCLUSION

Thirteen factors closely related to hospital stay duration and LOS prediction score could predict the prolongation of a patient's hospital stay.

[Two cases of advanced gastric cancer achieved pathological complete response by preoperative chemotherapy with S-1 plus weekly low-dose CDDP]

We report 2 cases of resectable advanced gastric cancer who achieved pathological complete response by preoperative chemotherapy with S-1 plus weekly low-dose cisplatin (CDDP). S-1 (80 mg/m²)was administered consecutively for 21 days followed by 14 days' rest, with CDDP (25mg/m²) injected on days 1, 8, and 21. Case 1: A man in his 70s diagnosed with cStage III gastric cancer with lymph node metastases received 2 courses of preoperative chemotherapy with S-1 plus weekly low-dose CDDP followed by total gastrectomy with D2 lymph node dissection. Case 2: A man in his 60s diagnosed with cStage III gastric cancer with lymph node metastases received 4 courses of preoperative chemotherapy with S-1 plus weekly low-dose CDDP followed by total gastrectomy with D2 lymph-node dissection. In both cases, postoperative pathological examination revealed no cancer cells in the resected stomach and lymph nodes. The therapeutic effect of preoperative chemotherapy was assessed as Grade 3. With this regimen, we accomplished preoperative chemotherapy successfully without inpatient care. This regimen can be a promising option as preoperative chemotherapy for advanced gastric cancer.

Ergonomic evaluation of a mechanical anastomotic stapler used by Japanese surgeons

Purpose

The satisfaction rating of currently available mechanical staplers for Japanese surgeons with small hands is low. To identify the issue, we examined the relationship of hand dimensions and grip force with the operation force of a mechanical circular stapler.

Methods

Hand dimensions and grip force were measured in 113 Japanese surgeons (52 men and 61 women). We then evaluated the relationship between grip width and the operation force required to push the lever of the stapler, at three points on the lever, using a digital force gauge.

Results

The optimal grip width of the dominant hand was 62.5 ± 8.5 mm for men and 55.5 ± 5.9 mm for women (p < 0.001). The maximum grip force of the dominant hand was 44.2 ± 6.1 kg for men and 29.7 ± 4.5 kg for women (p < 0.001) and the maximum operation force required to push the lever 7.0, 45.0, and 73.0 mm from the end of the lever was 21.8, 28.6, and 42.4 kg, respectively.

Conclusions

To our knowledge, this is the first ergonomic study of a surgical stapler to be conducted in Asia. Firing the stapler by gripping the proximal side of the lever is physically impossible for most Japanese women surgeons since the required operation force exceeds the maximum grip force, which probably accounts for the stress perceived by these women.

Multicenter phase II study of FOLFOX or biweekly XELOX and cetuximab as first-line treatment in patients with wild-type KRAS/BRAF metastatic colorectal cancer (mCRC) (FLEET study)

463

Background: Cetuximab and chemotherapy as first-line therapy for patients with KRAS wild type prolong survival. However, COIN trial has not demonstrated the survival benefit of FOLFOX or XELOX and cetuximab therapy. Few data are available on its benefit for patients with KRAS and BRAF wild-type. Methods: The aim of this study was to assess the efficacy of first-line FOLFOX or bi-weekly XELOX and bi-weekly cetuximab in KRAS/BRAF wt mCRC. Chemonaive patients received FOLFOX or biweekly XELOX (oxaliplatin 85 mg/ m2/day 1 plus capecitabine 2000/m2/days 1-7) and biweekly cetuximab 500mg m2/ day 1 every 2 weeks. Primary endpoint was response rate(RR), other secondary endpoints were PFS, OS, DCR, safety, DI and resection rate. KRAS test (codon12,13) and BRAF test (V600E) by direct sequence were performed in Yamaguchi University. Patients with KRAS/BRAF wt were enrolled in this study. The regimen of FOLFOX or XELOX were selected by investigator’s preference, not randomized. Results: From April 2010 to May 2011, 139 pts were preregistered. KRAS and BRAF were examined from paraffin-embedded sample. 70 (50.3%) pts were KRAS/BRAF wt, and 62 pts were enrolled: The main characteristics of the entered pts were: sex (M/F) 34/28, median age 66 yrs (range 34-83 yrs). Grade 3/4 adverse events were leucopenia 4.8%, neutropenia 25.8%, skin toxity (paronychia/fissure) 9.7%, and acne 9.7%. Two CR (3.2%) and 40 PR (64.5%), 15 SD (24.2%) and 3 PD (4.8%) 2NE were observed, with an overall response rate of 67.7% and a disease control rate (CR+PR+SD) of 91.9%. The RR of FOLFOX or XELOX were 64.9% (24/37) and 72.0% (18/25), DCR were 89.2% and 96% respectively. Conclusions: FLEET was the first multicenter phase II study with prospective KRAS/BRAF analysis as a predictive biomarker for cetuximab in first-line mCRC in Japan. Results of this study indicate that both biweekly combination regimens are feasible, tolerable, and clinically active. Biweekly XELOX+cetuximab study (FLEET2) is ongoing. Clinical trial information: UMIN000003253.

Self-monitoring of home blood pressure with estimation of daily salt intake using a new electrical device

We investigated a simple device to monitor daily salt intake at home and examined the relationship between salt excretion and morning blood pressure in order to enable patients to better manage daily salt intake and hypertension. The correlation between 24-h urinary salt excretion and measured value with salt monitor from overnight urine was significant (n = 224, r = 0.72, P < 0.001). A total of 46 volunteers participated for more than 3 weeks by measuring daily salt intake and morning blood pressure. The relationship between predicted daily salt excretion and blood pressure was examined with use of 3-day moving average. Mean salt excretion and systolic blood pressure (SBP) significantly decreased by the end of the trial (i.e., salt excretion decreased from 158+/-31 to 149+/-30 mmol/day and SBP from 137+/-17 to 133+/-16 mm Hg). Of 46 participants, 18 (39%) had a significant correlation between predicted daily salt excretion and blood pressure (r > 0.4, P < 0.05, n > 21), indicating sodium sensitivity. An additional 17% had a positive correlation that did not reach statistical significance (0.2 < r < or = 0.4), and the remaining 44% had no correlation (r < or = 0.2). Mean decrease in blood pressure per decrease in salt (g) (17 mmol) intake in the 18 participants with a significant correlation was 3.3 mm Hg (SBP) and 1.5 mm Hg (diastolic blood pressure), which was higher than that reported for other studies. Hypertensive patients not using medication showed the largest decrease. We conclude that daily monitoring of salt intake and morning blood pressure will be useful for management of hypertension.

Prevalence of Cryptosporidium parvum infection and pattern of oocyst shedding in calves in Japan

Cryptosporidium parvum infection and the pattern of oocyst shedding were observed in calves. A total of 480 fecal samples were collected from 30 calves (age, < or =30 days) over a period of 10 months from June 1998 to March 1999. A sucrose centrifugal flotation technique revealed 28/30 (93%) calves were passing Cryptosporidium oocysts. Oocyst shedding was first detected on the sixth day after birth, with 8% of the calves testing positive. This rate increased day by day and reached approximately 80% by day 15. Oocyst shedding varied from 1 to 13 days, with a mean of 7 days. Calves infected with C. parvum had a significantly higher rate of diarrhea (33%) than non-infected calves (8%) (P<0.05), suggesting C. parvum infection as the likely cause. The mean number of oocysts excreted by calves < or =30 days old was approximately 6x10(7) per gram of feces. These results indicated that one calf would excrete some 6x10(11) oocysts in the first month after birth, taking both the quantity of feces in a day and the period of excretion into consideration. Accordingly, it is clear that calves are important in the spread of cryptosporidiosis to calves and humans.

Mapping of interneurons that contribute to food aversive conditioning in the slug brain

To determine the distribution of neurons that contribute to memory formation induced by odor-taste associative conditioning in the slug's brain, we examined neuronal activity of the central nervous system of the slug Limax marginatus using a fluorescent activity marker [Lucifer yellow (LY)]. When LY was injected into the body cavity just after the conditioning, many of the procerebral (PC) interneurons were labeled. The PC lobe was considered to play important roles in the olfaction of the slug, because the olfactory afferent fibers from both the inferior and the superior tentacular noses innervate it. Such strong dye-uptake activity of PC interneurons was not observed when LY was injected just after unpaired control treatment. Thus, it was suggested that enhancement of dye-uptake activity upon conditioning was caused by the association of a conditioning stimulus (CS) with an unconditioned stimulus (UCS). The distribution patterns of PC interneurons that were labeled by LY after conditioning showed a characteristic feature: They usually formed a belt-shaped cluster parallel to the dorsoventral axis. This feature of the distribution was maintained when different odors were used as a CS. Furthermore, the number of the clusters reflected the number of CS odors but not the number of conditioning sessions. From these observations, we considered that enhancement of the neural activity involving dye uptake in each belt-shaped cluster contributed to formation of each odor memory.

Eruptive clear cell hamartoma of sweat duct

A histologically unique condition of the sweat duct was found in a miliaria-like papular eruption on the extensor surfaces of extremities of a 41-year-old female patient. The hypertrophic epithelium of the sweat duct wall consisted of extensively vacuolated clear cells. There was mild hyperkeratosis around the sweat duct orifice. The eccrine gland cells showed only partial vacuolization. Since this condition is not related to any of the other known benign changes of the eccrine duct, we report it with a presumptive descriptive diagnosis of eruptive clear cell hamartoma of sweat duct.

Time-resolved electron microscopic analysis of the behavior of myosin heads on actin filaments after photolysis of caged ATP

The interaction between myosin subfragment 1 (S1) and actin filaments after the photolysis of P3-1-(2-nitrophenyl)ethyl ester of ATP (caged ATP) was analyzed with a newly developed freezing system using liquid helium. Actin and S1 (100 microM each) formed a ropelike double-helix characteristic of rigor in the presence of 5 mM caged ATP at room temperature. At 15 ms after photolysis, the ropelike double helix was partially disintegrated. The number of S1 attached to actin filaments gradually decreased up to 35 ms after photolysis, and no more changes were detected from 35 to 200 ms. After depletion of ATP, the ropelike double helix was reformed. Taking recent analyses of actomyosin kinetics into consideration, we concluded that most S1 observed on actin filaments at 35-200 ms are so called "weakly bound S1" (S1.ATP or S1.ADP.Pi) and that the weakly bound S1 under a rapid association-dissociation equilibrium with actin filaments can be captured by electron microscopy by means of our newly developed freezing system. This enabled us to directly compare the conformation of weakly and strongly bound S1. Within the resolution of deep-etch replica technique, there were no significant conformational differences between weakly and strongly bound S1, and neither types of S1 showed any positive cooperativity in their binding to actin filaments. Close comparison revealed that the weakly and strongly bound S1 have different angles of attachment to actin filaments. As compared to strongly bound S1, weakly bound S1 showed a significantly broader distribution of attachment angles. These results are discussed with special reference to the molecular mechanism of acto-myosin interaction in the presence of ATP.

Elastic filaments in situ in cardiac muscle: deep-etch replica analysis in combination with selective removal of actin and myosin filaments

To clarify the full picture of the connectin (titin) filament network in situ, we selectively removed actin and myosin filaments from cardiac muscle fibers by gelsolin and potassium acetate treatment, respectively, and observed the residual elastic filament network by deep-etch replica electron microscopy. In the A bands, elastic filaments of uniform diameter (6-7 nm) projecting from the M line ran parallel, and extended into the I bands. At the junction line in the I bands, which may correspond to the N2 line in skeletal muscle, individual elastic filaments branched into two or more thinner strands, which repeatedly joined and branched to reach the Z line. Considering that cardiac muscle lacks nebulin, it is very likely that these elastic filaments were composed predominantly of connectin molecules; indeed, anti-connectin monoclonal antibody specifically stained these elastic filaments. Further, striations of approximately 4 nm, characteristic of isolated connectin molecules, were also observed in the elastic filaments. Taking recent analyses of the structure of isolated connectin molecules into consideration, we concluded that individual connectin molecules stretched between the M and Z lines and that each elastic filament consisted of laterally-associated connectin molecules. Close comparison of these images with the replica images of intact and S1-decorated sarcomeres led us to conclude that, in intact sarcomeres, the elastic filaments were laterally associated with myosin and actin filaments in the A and I bands, respectively. Interestingly, it was shown that the elastic property of connectin filaments was not restricted by their lateral association with actin filaments in intact sarcomeres. Finally, we have proposed a new structural model of the cardiac muscle sarcomere that includes connectin filaments.

Density values of the corpus callosum in schizophrenic brains

Density values of the corpus callosum and ventricular brain ratio (VBR) were obtained by coronal computerized tomography (CT) in 16 chronic schizophrenic patients and 16 normal controls. The corpus callosum of schizophrenic brains showed no apparent density loss which could indicate a dysfunctional brain. A significant ventricular dilatation was found in the patient group compared with age-matched controls. This finding was compatible with several former observations with transverse scanning.

Lesions of the mediodorsal thalamic nucleus do not change thresholds for hypothalamic defensive attack in cats

Electrolytic lesions of the mediodorsal thalamic nucleus (nMD) were made in 10 cats to evaluate their effects on thresholds for hypothalamic defensive attack and emotional reactivity to noxious stimuli. Only 2 cats showed minimal threshold changes after the lesions, one of which was accompanied by an increased emotional reactivity to noxious stimuli; however, this was attributed to damage to the fornical column. The nMD appeared not to be involved directly in the central mechanism of defensive attack.

Computerized tomographies of 34 patients at the chronic stage of acute carbon monoxide poisoning

The brains of 34 patients at the chronic stage of acute carbon monoxide poisoning (CO poisoning) were examined using computerized tomography (CT). Ventricular and sulcal dilatations were measured quantitatively, with picture analysis of CT for the measurement of ventricular dilatation. Significant ventricular and sulcal dilatations were found in all cases of the CO group compared with age-matched controls, and bilateral low density areas in the globus pallidus were seen in 9 of the patients. There were significant correlations between duration of initial unconsciousness and the ventricular dilatation or cortical atrophy. Such dilatations were considered to be due to the cerebral damage in the acute stage.

Comparison of three blood-clotting substances in Staphylococcus aureus strains

Besides the two well-known blood-clotting substances, coagulase and clumping factor, a third one has been identified from the staphylococci which is a cell surface polysaccharide, is alkali stable, and induces compact-colony formation in serum soft agar. Using some 97 clinical strains of Staphylococcus aureus, we found that in production and activity the substances were distinctly different.

Relation of colonial morphologies of strain of Streptococcus pneumoniae in soft-agar to the encapsulation

Among 40 fresh isolates of Streptococcus pneumoniae 12, 25 and 3 strains, respectively, exhibited large round, small round and compact colonial morphologies in soft-agar medium. Every large round strain possessed a capsule, almost half of the small round strains had capsules, while all of the large round type growth showed very high mouse virulence and 1.0 mg of these organisms was capable of absorbing a minimal amount of passive protective antibody in rabbit antiserum, prepared with the homologous strain, against challenge infection with homologous organisms in mice. Its variant showing compact type growth in soft-agar was mouse avirulent and a similar amount of the mouse passive protective antibody could not be absorbed with 100 mg of these organisms. These experimental results indicate that the soft-agar technique can be used for the identification of encapsulated strains of Streptococcus pneumoniae.

Passive protection by human serum in mice infected with encapsulated Staphylococcus aureus

The occurrence and nature of passive protective antibody in 100 samples of human serum was investigated in mice challenged with strains of Staphylococcus aureus capsular types A (Smith diffuse strain) and B (strain NS58D). Sixty of the sera passively protected mice against the capsular type-A strain, three against type B, and one against both types. Rabbit antisera against human IgG, IgA and IgM could remove the protective activity from a human serum of high potency, and the activity was also sensitive to 2-mercaptoethanol. Absorption with Smith surface antigen removed protective activity and reduced the concentration of IgG 7-fold, IgA 2.7 fold and of IgM 3-fold more than in a non-protective serum. Consequently, the protective activity of human serum is believed to be associated with antibodies to the S. aureus capsular antigen in the three immunoglobulin classes.

Electronmicroscopic finding of surface structure and capsular swelling reaction of a strain of Klebsiella pneumoniae

To investigate a capsular swelling reaction of the strain K-9 of Klebsiella pneumoniae, possessor of large capsule, ultra-thin sections of the organisms were stained with uranyl acetate and lead citrate and were treated with rabbit antiserum. The ultra-thin sections of above stained organisms showed spike-like structure in outmost layer of the cell wall. When they were treated with rabbit antiserum, the outmost layers of the organisms was surrounded by a zone of oval to round polymorphous vesicular structure which covered the spike-like appendages. These findings were assumed being capsular swelling reaction of these organisms. However, when they were treated with rabbit antiserum which was previously absorbed with the polysaccharide surface antigen, polymorphous vesicular structures did not appear and sharp spiked structures issuing from the cell wall were exposed.