The rostro-caudal position of cardiac myocytes affect their fate

During chick embryogenesis, cells destined to form cardiac myocytes are located within the primitive streak at stage 3 in the same relative anterior-posterior distribution as in the prelooped heart. The most rostral cells contribute to the extreme anterior pole of the heart, the bulbus cordis, and the most caudal to the extreme posterior end, the sinoatrial region. After gastrulation, these cells commit to the myocyte lineage and, retaining their relative positions, migrate to the anterior lateral plate. From stages 5 to 10 they diversify into atrial and ventricular myocytes, with the former located posteriorly and the latter, anteriorly. To determine the effect of a change in the rostro-caudal position of these cells on their diversification, anterior lateral plate mesoderm and the underlying endoderm were cut and rotated 180 degrees along the longitudinal axis, at stages 4-8. The subsequent diversification of these precursor cells into atrial and ventricular myocytes was examined using lineage-specific markers. Our results showed that altering location along the longitudinal axis through stage 6 changed the normal fate of a precursor cell. The orientation of the overlying ectoderm did not alter normal morphogenesis or determination of fate.

Safety and acceptability of a baggy latex condom

A total of 104 couples participated in a randomized crossover trial to compare a new baggy condom with a straight-shaft condom produced by the same manufacturer. Participants completed a coital log after using each condom. All couples used five condoms of each type. Among 102 couples who did not report major deviations from the protocol, the breakage rate was eight of 510 (1.6%) for the baggy condom, and six of 510 (1.2%) for the standard condom (rate difference, RD = 0. 4%, 95% confidence interval of the RD, CI = -1.0%; +1.8%). Slippage was reported in 50 baggy condom logs and in 58 standard condom logs; the slippage rate was 50 of 510 (9.8%) for the baggy condom, and 58 of 510 (11.4%) for the standard condom (RD = -1.6%, 95% CI = -5.4%; +2.2%). Slippage was most often partial (<1 inch) and may not indicate condom failure. Severe slippage rates were 11 of 510 (2.2%) for the baggy condom, and 18 of 510 (3.5%) for the standard condom (RD = -1.4%, 95% CI = -3.4%; +0.7%). The findings support the conclusion that the two condoms are equivalent with respect to breakage and slippage. The participants appeared to prefer the baggy condom, suggesting that the new product may be more acceptable to the public than the traditional straight-shaft condoms, and may be easier to use consistently over long time periods.

Cost of care for individuals with cystic fibrosis: a regression approach to determining the impact of recombinant human DNase

We estimated direct medical costs of care and important determinants of the costs in patients with cystic fibrosis (CF), including therapy with recombinant human DNase (rhDNase). Costs were estimated with resource use data from the Epidemiologic Study of Cystic Fibrosis. Ordinary least squares regression was used to determine the effect of clinical and demographic variables on individual cost of care. The estimated cost of caring for 303 patients in Alberta was $2,279,801 in 1996. The mean cost of care was $7524 (range $386-92,376)/patient. Regression results indicated that age and forced expiratory volume predicted had a negative association with costs. Being female, receiving rhDNase, and having Pseudomonas aeruginosa or Burkholderia cepacia were all associated with high costs. Our estimates indicated large interindividual variation in cost of care for patients with CF.

Resuscitation in the hospital: differential relationships between age and survival across rhythms

OBJECTIVE

Assess the frequency and outcome of inhospital resuscitation and determine the relationship between patient age and survival and whether it is affected by initial rhythm.

DESIGN

Retrospective, single-institution, registry study of inhospital resuscitation.

SETTING

A 550-bed, tertiary-care, teaching hospital in Macon, GA.

PATIENTS

All admissions for which a resuscitation was attempted in the Medical Center of Central Georgia during the period of January 1, 1987 through December 31, 1993. The registry sample included 2,394 admissions, for which 2,813 resuscitation attempts were made; only the first resuscitation attempt during an admission was analyzed.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Rates of survival to discharge steadily increased from 24.4% in 1987 to 38.6% in 1993; the overall survival rate was 26.8%. Age, used as a continuous variable, was strongly related to survival (odds ratio = 0.984; p < .0001). Categorically, overall survival rates for pediatric, adult, and geriatric patients were 56.4%, 29.0%, and 24.0%, respectively. Survival rates also varied significantly (odds ratio = 0.469; p < .0001) among initial rhythms, i.e., supraventricular tachycardia (60.7%), ventricular tachycardia (57.6%), perfusing rhythms (49.84%), ventricular fibrillation (32.0%), pulseless electrical activity (14.6%), and asystole (9.1%). The relationship between age and survival did not change across the years included in the study, but did vary as a function of initial rhythm (p < .0001). Age was positively related to survival when initial rhythm was supraventricular tachycardia (p = .04), negatively related to survival when the initial rhythm was perfusing (p < .0001) or pulseless electrical activity (p = .0002), and not related to survival when the initial rhythm was ventricular tachycardia (p = .98), ventricular fibrillation (p = .14), or asystole (p = .21).

CONCLUSIONS

The relationship between patient age and a successful resuscitation attempt is not as simple as reported earlier. Whether age is related to increased or decreased survival, or is unrelated to survival, depends on the rhythm extant when resuscitation attempts begin. Survival rates were higher than most reported elsewhere and improved significantly over time. Multicentered studies are needed to determine whether these results are unique to the institution studied.

A World Wide Web Internet engine for collaborative entry and peer review of radiologic teaching files

OBJECTIVE

Radiologists can now use the Internet as a dissemination medium for radiologic teaching files. This has greatly increased the availability of radiologic information to a larger number of people. However, the creation of the teaching files themselves remains a static and labor-intensive process. As a partial solution to this problem, we set out to create a World Wide Web-based Internet engine for the collaborative entry and peer review of radiologic teaching files.

CONCLUSION

We created a system that facilitates, simplifies, and improves the generation of radiologic teaching files. We used the Internet to help promote the creation of teaching files in a more timely, efficient, and effective manner.

Swallowing disorders after esophageal atresia evaluated with videomanometry

BACKGROUND

Patients with repaired esophageal atresia often show persistent motility disorders of the esophagus.

METHODS

In this study, the authors used a newly developed method, videomanometry, to study intraluminal pressures and function of the pharynx and upper esophagus in such a group of patients and compared the results with those in healthy age-matched controls.

RESULTS

A significant difference was found between timing of the pharynx contraction and upper esophageal sphincter (UES) relaxation, indicating a dyscoordination of swallowing in the patient group. Transit time of bolus from the pharynx to the esophagus was also shorter for the patient group. Such dyscoordination may be a risk factor that can cause aspiration and respiratory symptoms.

CONCLUSION

UES resting pressure and residual pressure on swallowing, did not differ between the two groups.

Immunostimulation of murine spleen cells by materials associated with bovine milk protein fractions

Purified bovine milk proteins that were added to cultures of murine spleen cells significantly increased cell proliferation and production of immunoglobulin M. Casein and a whey mixture consisting of alpha-lactalbumin, bovine serum albumin, bovine gamma globulin, and beta-lactoglobulin (beta-LG) were stimulatory. Of the three beta-LG preparations that are commercially available (beta-LG containing variants A and B, purified variant A, and purified variant B), the unseparated mixture containing both the A and B variants showed the most immunomodulatory activity. Both alkaline treatment and trypsin digestion of the beta-LG preparation markedly reduced its effectiveness. Polymyxin B, while greatly diminishing the stimulatory effect of lipopolysaccharide, had no significant effect on either the enhancement of cell proliferation or the enhancement of immunoglobulin production by beta-LG. In the presence of S-(n-butyl)-homocysteine sulfoxamine, the stimulatory effect of beta-LG on cell proliferation and IgM production in vitro was markedly reduced.

A clinicopathological study of autism

A neuropathological study of autism was established and brain tissue examined from six mentally handicapped subjects with autism. Clinical and educational records were obtained and standardized diagnostic interviews conducted with the parents of cases not seen before death. Four of the six brains were megalencephalic, and areas of cortical abnormality were identified in four cases. There were also developmental abnormalities of the brainstem, particularly of the inferior olives. Purkinje cell number was reduced in all the adult cases, and this reduction was sometimes accompanied by gliosis. The findings do not support previous claims of localized neurodevelopmental abnormalities. They do point to the likely involvement of the cerebral cortex in autism.

Impaired gastric emptying in children with repaired esophageal atresia: a controlled study

BACKGROUND

Scintigraphy is considered the "gold standard" for investigating gastric emptying. The lack of standards regarding registration technique and meal composition has been a problem especially in pediatric patients.

METHODS

In this study, gastric emptying of a solid meal was assessed by scintigraphy in 10 patients with repaired esophageal atresia (5 to 10 years old), and the results were compared with those in 11 healthy control children (5 to 11 years old). The meal consisted of pancakes with a fixed energy composition labeled with Tc-99m. Fractional meal retention values were plotted as a function of time.

RESULTS

Half-emptying time and lag phase values were longer in the patient group, whereas the emptying rate was slower and the retention values at 60 and 90 minutes were higher than in the control group. Extremely long lag phase and slow emptying rates were seen in two patients with reflux symptoms and abdominal complaints. Gastric emptying in healthy children has not previously been studied by scintigraphy. The results of this study show that values for gastric emptying of solids in healthy children correspond well to those reported in healthy adults.

CONCLUSION

Scintigraphy is an easy and reliable method for gastric emptying studies in children. The radioactive dose can be kept very low, which makes it a safe method even for pediatric patients. Delayed gastric emptying can occur in patients who have repaired esophageal atresia, and may be associated with reflux symptoms and abdominal complaints.

Alkalinization is ineffective for severe hyperkalemia in nonnephrectomized dogs. Hyperkalemia Research Group

OBJECTIVE

To determine whether alkalinization with sodium bicarbonate (NaHCO3) in near-lethal hyperkalemia either lowers potassium (K) rapidly or shortens duration of cardiac conduction disturbances.

METHODS

A controlled canine laboratory investigation of 3 treatments for severe hyperkalemia. Conditioned dogs (n = 8; 17-30 kg) received, in random order, 2 mmol/kg of each of 3 treatments (matched in sodium and water) in separate experiments > or = 1 week apart: 1.05% NaHCO3 over 60 minutes (infusion therapy); 8.4% NaHCO3 over 5 minutes, then 14 mL/kg sterile water over 55 minutes (bolus therapy); 8.4% NaCl over 5 minutes, then 14 mL/kg sterile water over 55 minutes (saline therapy). Prior to administering one of the above therapies, the animals were anesthetized with 0.5-2.5% isoflurane and ventilated to maintain a normal PCO2. After 30 minutes of equilibration, 2 mmol/kg/hr (loading dose) of a 2-mmol/mL KCl solution was given until idioventricular or relative junctional bradycardic dysrhythmias were sustained for 15 minutes. Then KCl was decreased to 1 mmol/kg/hr (maintenance dose) for 2 hours and 45 minutes. Treatment was begun after 45 minutes of maintenance KCl infusion.

RESULTS

The pretreatment K level (all studies) was 9.06 +/- 0.82 mmol/L (mean +/- SD). Although the mean K level decreased more after saline therapy than after bolus therapy at every time, differences were neither statistically significant nor clinically important during the first 30 minutes. The means of the differences in decreases (saline minus bolus) were small, 0.26 (95% CI, -0.48 to 1.00) at 15 minutes, 0.16 (95% CI, -0.67 to 0.98) at 30 minutes. Dysrhythmia duration was shorter with bolus therapy than for saline therapy in only 1 of 5 dogs (p = 0.38).

CONCLUSIONS

Hypertonic saline bolus lowered plasma K as effectively as NaHCO3 bolus in this animal model within the first 30 minutes. Clinically meaningful decreases due to alkalinization alone within 30 minutes are unlikely.

Gynecologic disorders in the older patient

This review addresses the presentation and management of gynecologic disorders in older women. While these conditions are often managed by a primary caregiver, many women may present to the ED because they lack a primary gynecologic caregiver, their established gynecologic caregiver is not available, they are embarrassed to discuss their symptoms with an established caregiver, or they seek immediate relief of symptoms and reassurance. The emergency physician (EP) must be aware of the normal physiologic changes that occur with aging and how these changes may produce symptoms in older women. This review addresses physiologic changes and pathophysiologic conditions. Knowledge of these conditions and their management will facilitate reassurance of the patient, expedite appropriate initial therapy, and enable the EP to efficiently refer patients requiring further gynecologic assessment.

Esophageal atresia: mortality and complications related to gastroesophageal reflux

Low birthweight and associated anomalies are important risk factors in patients with esophageal atresia. Gastroesophageal reflux is also a common problem in these patients and can lead to serious complications. The aim of this retrospective study was to analyse complications and mortality in 110 patients treated for esophageal atresia between January 1971-December 1987, in order to determine what role reflux may play. Symptoms of reflux were common in most patients during the first years of life. In some cases the symptoms were serious and even caused some late deaths by aspiration. The overall mortality was 12% (13/110). Early mortality (six patients) was caused by prematurity and associated anomalies, whereas late mortality often was caused by aspiration or other respiratory complications. Patients who had been operated with a circular myotomy showed more complications, but did not show a higher mortality rate than the remainder. This study confirms the importance of identifying patients with reflux at an early stage in order to prevent serious complications and mortality.

Conjugal amyotrophic lateral sclerosis: report of a young married couple

We report a 38-year-old nurse who developed amyotrophic lateral sclerosis (ALS) beginning in September 1990. In May 1991, her 38-year-old husband developed dysarthria, which progressed to typical ALS. This is the fourth report in the literature of conjugal ALS occurring outside of Guam. Although this event is most likely due to coincidence, exogenous agents should be considered in the etiology of ALS.

Laparoscopic-assisted excision of a solitary cecal ulcer

Laparoscopic-assisted excision of a solitary cecal ulcer that presented with right lower quadrant pain in a 61-year-old male is described. The patient benefited from complete surgical excision of his disease and he experienced a rapid postoperative recovery similar to that of other laparoscopic procedures, while foregoing the postoperative discomfort and morbidity associated with celiotomy. Excision of a complicated, benign cecal ulcer requires minimal bowel resection and is particularly amenable to laparoscopic assistance for minimally invasive access. For cecal ulcers requiring operative intervention, laparoscopy offers an alternative to open celiotomy.

Different patterns of neuropathological disease in rhesus monkeys infected by simian immunodeficiency virus, and their relation to the humoral immune response

The brains of 21 rhesus monkeys inoculated with SIVMAC251 were examined after intervals ranging from 3 to 27 months and compared with five uninoculated controls. Eighteen animals became infected and individually exhibited several distinct patterns of disease. Nine (50%) had largely intramural leptomeningeal venous infiltrates (LMVI) without multinucleate giant cells (MGC) or foamy macrophages. Three (17%) had only MGC lesions, involving the cerebral parenchyma. One had both patterns and five (33%) neither. The controls had sparse and tiny LMVI only, similar to three inoculated animals that did not become infected. Immunohistochemistry showed the predominance of T and B lymphocytes in LMVI and choroid plexus mononuclear lesions but a predominance of macrophages over lymphocytes in the MGC lesions. Specific disease patterns differed in their association with the humoral immune response. Animals with LMVI were all hypergammaglobulinaemic when killed compared to pre-inoculation levels, and the size of the change in serum immunoglobulin concentration was positively correlated with a quantitative index of LMVI density. Furthermore, their post-mortem lymph node histology was hyperplastic. In contrast, animals found at autopsy to have MGC brain lesions were hypogammaglobulinaemic compared to preinoculation. The results are consistent with two phases in SIV-associated disease: one characterized by LMVI and hypergammaglobulinaemia and another featuring MGC and hypogammaglobulinaemia.

A multicenter, randomized, double-blind, placebo-controlled, dose-titration study of oral pilocarpine for treatment of radiation-induced xerostomia in head and neck cancer patients

PURPOSE

To determine the efficacy and safety of pilocarpine hydrochloride for symptomatic relief of postradiation xerostomia symptoms and for saliva production in patients with head and neck cancer.

PATIENTS AND METHODS

One hundred sixty-two head and neck cancer patients who had received at least 40 Gy of radiation (117 patients had received > 60 Gy) with clinically significant xerostomia were enrolled onto a randomized, double-blind, placebo-controlled, multi-center clinical investigation. Patients received 2.5-mg tablets for the first 4 weeks, 5.0-mg tablets for the second 4 weeks, and 10.0-mg tablets for the last 4 weeks of the 12-week study. Patients were allowed to titrate pilocarpine or placebo for improvement in symptoms or to reduce side effects. Patients were evaluated for symptomatic relief by questionnaires and visual analog scales (VAS), and for saliva production by sialometry.

RESULTS

Pilocarpine produced a significant improvement (P = .035) in overall global assessments compared with placebo. There was a statistically significant (P = .020) decreased use of oral comfort agents such as artificial saliva, hard candy, and water. Values for symptomatic improvement in dryness approached significance (P = .057). There were statistically significant postdose improvements in whole and parotid salivary flow in pilocarpine treatment groups versus placebo. All pilocarpine dosages tested were judged to be safe. Adverse experiences were primarily sweating, rhinitis, headache, nausea, and urinary frequency, with the most common side effect being mild to moderate sweating. There were no serious drug-related adverse experiences in any of the pilocarpine treatment groups.

CONCLUSION

It is concluded that pilocarpine produces clinically significant benefits for the symptomatic treatment of postradiation xerostomia. Best results were obtained with continuous treatment for 8 to 12 weeks with doses greater than 2.5 mg three times per day.

Hematopoietic stem cell deficit of transplanted bone marrow previously exposed to cytotoxic agents

High-dose chemotherapy and/or total body irradiation followed by autologous bone marrow rescue has improved the survival of patients with a variety of malignancies. Candidates for autologous bone marrow transplantation (ABMT) often have received prior exposure to cytotoxic agents, some of which may damage primitive stem cells. We have developed an in vivo murine model to evaluate the effects of a number of individual cytotoxic agents on the ability of syngeneic donor marrow to provide long-term hematopoiesis in recipients following high-dose total body irradiation. Marrow was experimentally obtained by giving donor mice 6 weekly injections of saline, cytosine arabinoside, cyclophosphamide, cisplatin, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), or busulfan, drugs known to have differing effects on primitive hematopoietic stem cells. After time to allow recovery of marrow and peripheral blood counts, 1 x 10(7) marrow cells from these mice were transplanted into lethally irradiated syngeneic recipients. Five to 6 months after marrow transplantation, the quality of long-term hematopoietic recovery was measured by WBC counts, marrow cellularity, CFU-S content, and determinations of stem cell self-renewal. Abnormalities were noted with the use of donor marrow exposed to all cytotoxic agents. Recipients of marrow previously exposed to cytosine arabinoside, an agent that spares the most primitive stem cells, were the least affected. Recipients of marrow previously exposed to busulfan, an agent known to damage primitive stem cells, were most affected with a decrease in peripheral blood counts, marrow cellularity, stem cell content, self-renewal capacity, and long-term survival. A decrease in hematopoietic stem cell self-renewal was seen in recipients of marrow previously exposed to cyclophosphamide, cisplatin, and BCNU even when marrow cellularity and CFU-S content were normal. These data suggest that the capacity of syngeneic donor marrow to provide long-term hematopoiesis in lethally irradiated recipients is dependent on its donor marrow primitive stem cell content. Long-term hematopoiesis may be severely compromised in recipients of donor stem cells previously exposed to cytotoxic agents which damage primitive stem cells.

Relationship between response to inhaled salbutamol and methacholine bronchial provocation in children with suspected asthma

Fifty children (27 females, 23 males) ages 6-15 years who were referred for evaluation of suspected asthma had baseline FEV1 and FEF25-75 of greater than or equal to 80% and FEF50 greater than or equal to 70% of predicted values. All had these tests repeated on the same day, after inhaling salbutamol. On a subsequent day PC-20 (methacholine) was determined as an index of bronchial hyperreactivity (BH). Fourteen age-matched healthy children (6 females, 8 males) were studied in a similar manner. There was no significant relationship between the PC20 and the change in FEF25-75 or FEF50 following salbutamol. There was a negative correlation between the initial FEV1 (% predicted) and the percent change in FEV1 following salbutamol (P less than 0.01). An increase in FEV1 of greater than 6% occurred in 7/12 (58.3%) patients with PC20 less than or equal to 0.25 mg/mL (Group I); in 7/24 (29.2%) patients with PC20 = 0.26-2.0 mg/mL (Group II); in only 1/14 (7.1%) patients with PC20 greater than 2.1 mg/mL (Group III) and in none of those asymptomatic (control) children with PC20 greater than 8.0 mg/mL (Group IV). All subjects who had a change in FEV1 greater than 6% after salbutamol had a PC20 less than 8 mg/mL and this test detected the majority of patients with severe BH. However, although the sensitivity of the test was 100%, the predictive value was only 36%. We conclude that in the presence of a normal baseline FEV1 a change of greater than 6% following salbutamol inhalation is indicative of bronchial hyperreactivity.

[The effect of ipratropium bromide on lung function in patients with cystic fibrosis]

The main manifestation of cystic fibrosis (CF) of the lungs is an obstructive ventilation disturbance. The fact that the administration of atropine improves pulmonary function in patients with CF suggests a vagal mechanism for the development of bronchal obstruction. In a single-blind, placebo-controlled study, we investigated the effect of 250 micrograms of an inhalation solution of the anticholinergic substance ipatropium bromide (IB) on the pulmonary function of 11 patients with CF (age range: 8 to 29 years). The mean figures for the changes in FEV1.0, FEF25-75%, RV and TLC after inhalation of IB and placebo did not differ significantly. However, FEV1.0 and FEF25-75% after administration of IB increased in 4 out of 11 patients, and decreased in one. The lung volumes changed significantly in only a single case. This variable effect of inhaled IB in CF patients is in agreement with findings that have been observed for other substances with a "bronchodilatory" effect in patients with CF.

Home measurement of oxygen saturation during sleep in patients with cystic fibrosis

Feasibility and reproducibility of home measurement of arterial oxygen saturation (SaO2) were evaluated in 14 clinically stable patients with cystic fibrosis (CF). Changes in SaO2 during sleep were compared to the clinical status and pulmonary function while awake to identify predictors of nocturnal oxyhemoglobin desaturation. Each patient was assessed by clinical score, spirometry, and arterial blood gas analysis within 72 hours of the overnight study. Eight patients were studied on more than one occasion to assess dependence of SaO2 on position and reproducibility of overnight studies. A pulse oximeter stored up to 8 hours of nocturnal SaO2 measurements in its memory. Off-line analysis of trend data provided the proportion of sleep with SaO2 less than 90% and less than 85%. We found that patients with daytime PaO2 less than 60 mm Hg spent greater than 80% of their sleep with SaO2 less than 90%, while those with PaO2 greater than 70 mm Hg spent less than 20% of the night with SaO2 less than 90%. Patients with daytime PaO2 of 67-70 mm Hg were desaturated to less than 90%, from 0 to 98% of the night. No consistent body position dependence of daytime SaO2 was found. Home measurement of SaO2 during sleep was reproducible, with a difference on two repeat occasions of 4% +/- 2 (mean +/- SEM) for %time with SaO2 less than 90% and 3% +/- 2 for %time with SaO2 less than 85%. The severity of hemoglobin desaturation during sleep could not be reliably predicted from clinical scores or awake pulmonary function.(ABSTRACT TRUNCATED AT 250 WORDS)