Preliminary traction and the use of under-thigh pillows to prevent avascular necrosis of the femoral head in Pavlik harness treatment of developmental dysplasia of the hip

One hundred and sixty-one hips of 145 patients were treated with the Pavlik harness for developmental dysplasia of the hip. The patients were divided into two groups. Group A consisted of 65 patients (70 hips) who were treated between 1980 and 1987. The harness was applied immediately after the diagnosis. Group B consisted of 80 patients (91 hips) who were treated between 1988 and 1992. These patients received preliminary traction, and small pillows supported the lower extremities from just above the knee to the foot to prevent extreme abduction when the harness was applied. When the distance from the middle point of the proximal metaphyseal border of the femur to the Y-line (distance "a") was 8 mm or more on the initial X-ray picture, the rate of avascular necrosis in group A was 11% and that in group B was 0%; the difference was significant. However, when distance "a" was less than 8 mm, the rate of avascular necrosis in group A was 13% and that in group B was 12%, and there was no significant difference. Thus, we suggest that the Pavlik harness is indicated for developmental dysplasia of the hip in which distance "a" is 8 mm or more. Traction should precede application of the harness, and pillows placed under the thigh must be used during application.

Establishment of orally-administered Lactobacillus gasseri SBT2055SR in the gastrointestinal tract of humans and its influence on intestinal microflora and metabolism

AIMS

To investigate the fate of a streptomycin-rifampicin-resistant variant of Lactobacillus gasseri SBT2055 (LG2055SR) and the influence of its oral administration on the composition and metabolism of the intestinal microflora.

METHODS AND RESULTS

Intestinal passage of LG2055SR was monitored by a combination of selection with antibiotics and identification by a randomly amplified polymorphic DNA (RAPD)-PCR METHOD: Composition of intestinal microflora was analysed by the method developed by Mitsuoka et al. (1965, 1974). Establishment of orally-administered LG2055SR in the human intestine was confirmed in this study. LG2055SR ingestion specifically lowered faecal populations of Staphylococcus and faecal contents of p-cresol.

CONCLUSION

LG2055SR and its parent strain, LG2055, are considered to be appropriate candidates for probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

It is clarified that LG2055SR has the ability to establish in the human gastrointestinal tract and alters the composition and metabolism of the intestinal microflora and physical characteristics of faeces.

Chronic effects of different fatty acids and leptin in INS-1 cells

The effects of long-term exposure of a pancreatic beta cell line, INS-1, to major free fatty acids (FFA; palmitic acid, oleic acid and linoleic acid) and leptin on insulin secretion and cell viability by C,N-diphenyl-N'-4,5 dimethylthiazol 2-yl tetrazolium bromide (MTT) assay were examined. The cells were incubated with 1 mmol/l of each FFA and 25 or 100 ng/ml leptin, alone or in combination, for 4, 24 or 48 h before the insulin secretion experiments. Palmitic acid (C 16:0) significantly suppressed cell viability, and suppressed insulin secretion at 24 h. Treatment with oleic acid (C 18:1) or linoleic acid (C 18:2) enhanced basal insulin secretion and diminished glucose-stimulated insulin secretion (GSIS) at 48 h. In these groups, there were no differences in cell viability as compared to cells treated without FFA. Leptin did not affect insulin secretion at 4, 24 and 48 h, and in the cells co-treated with FFA and leptin, leptin did not ameliorate lipotoxicity. These results suggest that, in INS-1 cells, different FFA have different patterns of lipotoxicity with chronic exposure, and leptin has little direct effect on insulin secretion.

Arthroscopic treatment for traumatic hip dislocation with avulsion fracture of the ligamentum teres

Traumatic hip dislocation in children is a rare condition. Immediate closed reduction is a treatment of choice, but when incongruent reduction results, it can be due to interposition and requires open arthrotomy. We present a previously unreported technique of arthroscopic treatment that was used successfully for traumatic hip dislocation in a 10-year-old girl with impingement of the avulsed ligamentum teres. Arthroscopy was effective in confirming the exact nature of the interposition material and excising the fragment with minimal invasion.

Intestinal transit of an orally administered streptomycin-rifampicin-resistant variant of Bifidobacterium longum SBT2928: its long-term survival and effect on the intestinal microflora and metabolism

AIMS

The objectives of this study are to investigate the fate of a streptomycin-rifampicin-resistant variant of Bifidobacterium longum SBT2928 (BL2928SR) and the influence of its oral administration on the composition and metabolism of the intestinal microflora.

METHODS AND RESULTS

Intestinal passage of BL2928SR was monitored by a combination of selection with antibiotics and identification by a randomly amplified polymorphic DNA (RAPD)-PCR method. Intestinal microflora was analysed by the method developed by Mitsuoka et al. (1965, 1974). Long-term survival of orally administered BL2928SR in the human intestine was confirmed. BL2928SR ingestion specifically lowered faecal populations of Enterobacteriaceae and clostridia, including lecithinase-positive Clostridium spp.

CONCLUSION

BL2928SR and its parent strain, BL2928, are considered to be appropriate candidates for probiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

It is clarified that BL2928SR has the ability for long-term survival in the human gastrointestinal tract, and alters the composition and metabolism of the intestinal microflora.

Pitfalls in the toxicological analysis of an isobutyl nitrite-adulterated coffee drink

A forensic investigation was carried out on one poisoning case, where cyanide was first detected in an evidence sample of a canned coffee drink. A more complete study revealed that it had been adulterated with isobutyl nitrite (IBN) and not cyanide. We examined the detectivity of IBN and related compounds by headspace gas chromatography and capillary electrophoresis. IBN decomposes to isobutyl alcohol (iBuOH) and nitrite in aqueous solution, and under higher temperature and more acidic conditions, the rate of this reaction becomes more rapid. IBN was also produced by the esterification of iBuOH with nitrite below pH 5. Cyanide was produced in a coffee solution by the addition of nitrite below pH 6. An IBN-spiked canned coffee drink solution was stored at 4 degrees C and periodically analyzed for IBN, iBuOH, nitrite, nitrate, and cyanide. Since the IBN level decreased rapidly, iBuOH was produced in an almost 90% molar yield. Nitrite production reached a maximum of 40% molar recovery on the first day and then gradually disappeared. The nitrate level reached a plateau of approximately 60% molar recovery. Cyanide was also detected, and its level at the 14th day was approximately 0.26% molar recovery. These findings suggest that, in a coffee drink solution, IBN undergoes hydrolysis to produce iBuOH and nitric acid, which is oxidized to nitrate and also produces cyanide through the nonspecific oxidation of organic compounds under acidic conditions.

Wider indications for the local resection of gastric cancer by adjacent lymphadenectomy

BACKGROUND AND OBJECTIVES

A variety of minimal invasive treatment strategies for early gastric cancer without reducing the curability have been introduced, however, the indications for the local resection of early gastric cancer have not been precisely established.

METHODS

Two approaches are adopted in this study to elucidate indications for local resection. One is a retrospective review of surgically resected, postoperatively histologically proven early gastric cancers between 1976 and 1996 (611 patients), and the other is the patient selection from those who underwent modified D(1) lymphadenectomy in a prospective manner between 1987 and 1996, based on the preoperative and intraoperative diagnoses of mucosal, node negative, nonpalpable gastric cancer (125 patients). In these approaches, patterns of nodal involvement in association with clinicopathological characteristics of gastric cancer were investigated.

RESULTS

The depressed with ulceration type and histologically high grade type were predominant characteristics of mucosal, node positive gastric cancer patients. Of these patients, after the exclusion of those who were diagnosed to have submucosal or advanced cancer preoperatively or who had palpable cancer intraoperatively, the gastric cancer < or =4 cm in maximum diameter had positive nodes confined to only one station adjacent to the cancer without simultaneous nodal involvement in the other stations.

CONCLUSIONS

Local resection can be performed for gastric cancers < or = 4 cm in maximum diameter that meet our criteria for modified D(1) lymphadenectomy, in association with the frozen section confirmation of cancer negative in the simultaneously dissected lymph nodes in the stations adjacent to the cancer. The adjacent lymphadenectomy and frozen section examination make the application of local resection possible for a wider segment of patients.

Efficiency of pretreatment of aqueous samples using a macroporous strong anion-exchange resin on the determination of nerve gas hydrolysis products by gas chromatography-mass spectrometry after tert.-butyldimethylsilylation

A pretreatment procedure, using a macroporous strong anion-exchange resin (MSA) has been established for the determination of nerve gas hydrolysis products by gas chromatography-mass spectrometry (GC-MS) after tert.-butyldimethylsilyl (TBDMS) derivatization. Aqueous solutions of methylphosphonic acid (MPA) and three alkyl methylphosphonic acids (AMPAs) (ethyl, isopropyl and pinacolyl methylphosphonic acid), were retained on the MSA column, and then quantitatively eluted with 0.1 M hydrochloric acid. The neutralized column eluate was dried, and MPA and AMPAs were derivatized with N-methyl-N-(tert.-butyldimethylsilyl)-trifluoroacetamide and analyzed by GC-MS. The column eluate was also analyzed in order to determine the exact hydrolysis product levels by capillary electrophoresis using borate and benzoate buffer (pH 6). The MSA pretreatment was examined for the clean-up of aqueous extracts of three types of soils and an aqueous solution containing 10% sucrose, which is regarded as model for a typical soft drink, after spiking with MPA and AMPAs. MPA and AMPAs were quantitatively recovered in the MSA eluate fraction from those samples, except for MPA from volcanic acid and alluvial soils. The yields of TBDMS derivatives were remarkably improved, compared with for which no pretreatment was used and also for those in which a strong cation-exchange resin was used. The achieved detection limits of MPA and AMPAs ranged from 0.12 to 0.18 microg/g of soil (S/N=3). The established MSA method was applied to the pretreatment of spiked sea water, two types of beverages, Pepsi Cola and canned coffee. Although the yields of TBDMS derivatives of MPA and AMPAs in sea water (in a range between 44 and 96%) and AMPAs in Pepsi Cola (in a range between 58 and 92%) were rather high, those for MPA in the Pepsi Cola (27%) and those for MPA and AMPAs in the canned coffee (in a range between 5 and 17%) were low.

Early characteristic findings in bowleg deformities: evaluation using magnetic resonance imaging

We used magnetic resonance imaging (MRI) to evaluate bowleg deformities in infancy. Twenty-five tibiae of 13 infants were examined and divided into two groups based on MRI findings: group A had high intensity area in the medial epiphyseal cartilage on T2-weighted images. Group B had depression of medial physis and abnormal signal in the perichondrial region in addition to the epiphyseal lesion. At the final follow-up, all cases in group A demonstrated normal lower leg alignments, whereas five cases in group B showed characteristic roentogenographic findings of Blount's disease. The improvement rate of metaphyseal-diaphyseal angle was correlated with this classification. These findings suggested that abnormal findings in physis and perichondrial region might be preliminary findings in early stage of Blount's disease. The high intensity areas in the medial epiphyseal cartilage were commonly found among the cases with bowing deformities, which suggested that there might be a common pathomechanism between physiologic bowing and infantile Blount's disease.

Vascular invasion of early gastric cancer at resection line

Vascular invasion is observed in early gastric cancers (EGCs) as well as advanced gastric cancers. However, there have been no studies assessing adequate surgical margins for EGCs with reference to vascular invasion. A total of 452 EGCs were retrospectively evaluated. Vascular invasion, via lymphatics and/or venous vessels, was examined histologically. The distance from the tumor edge to infiltration was measured when cancer cells extended beyond the tumor through vessels. Vascular invasion was histologically confirmed in 41 EGCs (9.1%). Invasion was in one-fourth (40/166, 24.1%) of submucosal cancers, but in only one (1/286, 0.3%) mucosal cancer. Five EGCs (1.1%) showed infiltration beyond the tumor through the vessels and the maximum distance from the tumor edge to the most distal site of infiltration was 4 mm. In conclusion, a 2 cm surgical margin, as recommended in Japanese surgical textbooks, is adequate for EGCs with reference to vascular invasion.

Major change in the predominant type of "Norwalk-like viruses" in outbreaks of acute nonbacterial gastroenteritis in Osaka City, Japan, between April 1996 and March 1999

In Osaka City, Japan, between April 1996 and March 1999, a total of 350 fecal specimens from 64 outbreaks of acute nonbacterial gastroenteritis were examined to investigate infection by "Norwalk-like viruses" (NLVs). By reverse transcription (RT)-PCR, 182 samples (52.0%) from 47 outbreaks (73.4%) were NLV positive. During those three years, the incidence of NLV-associated outbreaks showed seasonality, being higher during January to March (winter to early spring). The ingestion of contaminated oysters was the most common transmission mode (42.6%). The amplicons of the 47 outbreak strains that were NLV positive by RT-PCR were tested using Southern hybridization with four probe sets (Ando et al., J. Clin. Microbiol. 33:64-71, 1995). Forty of the outbreak strains were classified as 4 probe 1-A (P1-A) strains, 6 P1-B strains, 10 P2-A strains, 17 P2-B strains, and 3 untypeable strains, and the other 7 outbreaks were determined to be mixed-probe-type strains. Probe typing and partial sequence analysis of the outbreak strains indicated that a predominant probe type of NLVs in Osaka City had drastically changed; P2-B strains (77.8%) with multiple genetic clusters were observed during the 1996-97 season, the P2-A common strain (81.3%) related to the Toronto virus cluster was observed during the 1997-98 season, and P1-B strains (75.0%) with a genetic similarity were observed during the 1998-99 season. For the three untypeable outbreak strains (96065, 97024, and 98026), the 98026 outbreak strain had Southampton virus (SOV)-like sequences, and each of the other outbreak strains had a unique 81-nucleotide sequence. Newly designed probes (SOV probe for the 98026 outbreak strain and the 96065 probe for the 96065 and 97024 outbreak strains) were hybridized with relative strains and without other probe type strains. The prevalent NLV probe types in Osaka City during those three years were classified in six phylogenetic groups: P1-A, P1-B, P2-A, P2-B, SOV, and 96065 probe types.

Influence of gastrectomy on the distribution of intravenously administered 5-fluorouracil to regional lymph nodes in an animal model

BACKGROUND

Neoadjuvant and postoperative chemotherapies have been widely employed for the treatment of patients with gastric carcinoma. However, to the authors' knowledge there have been no studies that focused on pharmacokinetic differences between antineoplastic agents administered before versus after gastrectomy. The influence of gastrectomy on the distribution of antineoplastic agents, especially to the regional lymph nodes, were examined.

METHODS

Twelve pigs were divided into 2 groups of 6 each (i.e., those with and without total gastrectomy). Under general anesthesia, 10 mg/kg of 5-fluorouracil (5-FU) was injected rapidly. Total gastrectomies were performed before these injections in the group that underwent gastrectomy. In both groups a lymph node at the root of the left gastric artery (1), a preaortic lymph node (2), and venous blood were sampled in 3 animals at 15 minutes and in another 3 animals at 60 minutes after the 5-FU injection. The 5-FU concentrations in these samples were determined by high performance liquid chromatography.

RESULTS

The 5-FU concentrations of 1, 2, and plasma at 15 minutes/60 minutes after injection in the nongastrectomized group were 7.75 x 10(3)/227 ng/g, 7.58 x 10(3)/439 ng/g, and 7.24 x 10(3)/417 ng/mL, respectively. The corresponding concentrations in the gastrectomized group were 6.04 x 10(3)/211 ng/g, 5.80 x 10(3)/206 ng/g, and 5.76 x 10(3)/229 ng/mL, respectively. There were no differences in 5-FU concentrations among any of the lymph nodes or the plasma, regardless of whether gastrectomy was performed.

CONCLUSIONS

No influence of gastrectomy on the distribution of 5-FU to the regional lymph nodes was observed in animal models in the current study.

Exposure and dissection of the root of the right gastric artery during gastric surgery

A technique, by which the root of the right gastric artery can be clearly exposed and the area of the right gastric artery can thus be completely dissected, is presented herein. In conventional procedures, the approach to the right gastric artery is performed from the lesser omentum, and a lymphadenectomy along the common hepatic artery is carried out after the division of the right gastric artery. Using the present technique, the common hepatic artery is exposed before the exposure of the right gastric artery and lymph node dissection is thus continued peripherally to the proper hepatic artery. During these procedures, the root of the right gastric artery arising from the hepatic artery can be easily identified. The lymphatic flow from the area of the right gastric artery to that of the common hepatic artery is transected using the conventional procedure, but not with the present technique. In addition, an en bloc dissection of the regional lymph nodes is also possible when using this procedure.

An experimental study of intramural blood supply network of the stomach wall

BACKGROUND/AIMS

A fundamental experiment was undertaken with reference to local resection with lymphadenectomy for gastric cancer. The intramural blood supply network of the stomach wall, about which no reports have previously appeared, was surgically investigated.

METHODOLOGY

Five pigs were used. The left gastric and the right gastroepiploic vessels and their branches were removed from all the animals. The right gastric vessels were also removed, while the short gastric and the left gastroepiploic vessels were preserved in the 1st pig. Only the short gastric vessels were preserved in the 2nd, and the right and the short gastric vessels in the 3rd. After resection of the whole stomach with the spleen, angiography was performed through the preserved arteries. The 4th and 5th pigs underwent the same procedures as the 1st, with additional local resection of the stomach in the 5th. Both pigs were maintained for 1 year and then, angiography was performed.

RESULTS

When the short gastric and the left gastroepiploic vessels, or the short and the right gastric vessels were preserved, the whole stomach continued to receive blood supply through the intramural network. Stomach wall resection therefore can be performed with no complications after these procedures.

CONCLUSIONS

The present results confirm the possibility of local resection with lymphadenectomy as a treatment for gastric cancer.

An operative procedure for advanced Kienböck's disease. Excision of the lunate and subsequent replacement with a tendon-ball implant

Excision of the lunate and subsequent replacement with a tendon implant was performed in 22 patients with Kienböck's disease between 1971 and 1985. This procedure was indicated mainly for those with advanced Kienböck's disease, i.e., stage III or IV according to the Lichtman classification. After the collapsed lunate is removed, a tendon-ball implant, made of the palmaris longus and plantaris tendons is placed in the resultant space in the carpus. A forearm distractor is applied during the operation, and distraction is continued for 4 weeks postoperatively. We report the long-term results in 15 patients, whose average follow-up period was 16 years and 3 months. One patient with infection was excluded from the study because the implanted tendon was removed 2 weeks after the operation, and 6 patients were lost to follow-up. All patients were free of pain after the surgery. The flexion-extension range of the wrist increased by 14.2 degrees, on average, after the surgery. The average grip power of the operated hand was 90.2% of that in the non-operated hand. Calcification and ossification were frequent in the implanted tendons a few months postoperatively. The average carpal height ratio (defined as carpal height/length of the third metacarpal) was 0.53 before the operation and 0.49 at the time of follow-up. According to Dornan's classification of clinical results, 9 of the 15 patients were classified as having excellent results and 6 as good.

Preliminary report on local resection with lymphadenectomy for early gastric cancer

BACKGROUND

The frequency of lymph node metastasis in mucosal gastric cancers 2-4 cm in diameter was low (three (1.3 per cent) of 234) in patients treated in this unit between 1966 and 1995. This study was a prospective report on local resection with lymphadenectomy for early gastric cancer.

METHODS

Eight patients with a single early gastric cancer underwent local resection with lymphadenectomy. The tumour was excised with a non-cancerous rim of approximately 2 cm. The extent of lymphadenectomy depended on tumour location. Intraoperative endoscopic examination and frozen-section analysis of the dissected nodes were used to determine the resection line and evaluate nodal status.

RESULTS

Mean operating time, blood loss and number of dissected nodes were 171 min, 87 ml and 8 respectively. There were no operative complications. Cancer invasion was confined to the mucosa in six tumours but two patients had minute submucosal invasion. The maximum diameter of the resected specimens was 10 cm and no nodal involvement was detected. No patient developed postgastrectomy syndrome.

CONCLUSION

For selected patients with early gastric cancer, local resection with lymphadenectomy can provide a good quality of life without compromising cure rate.

Prefabricated free jejunal transfer: a new reconstructive technique for high pharyngeal defects

A new method that uses a prefabricated free jejunal transfer has been applied to three cancer patients with pharyngoesophageal defects with a high pharyngeal deficit extending up to the nasopharynx. In this method, the jejunum harvested in the usual manner is divided into two segments with a single vascular pedicle. Its distal segment is used to reconstruct the cervical esophagus, and its proximal segment is turned over to create a mucosal patch to cover the high pharyngeal defects. The two segments are then co-apted in a side-by-side anastomosis. The esophagus can be reconstructed in a naturally straight shape without a curved portion or blind loop formation, thus leading to good swallowing function. In our series, all grafts survived well and there was no complication directly related to jejunal transfer. All patients could tolerate a soft diet without difficulty. This method is easy to perform and applicable to any shape or size of very high pharyngeal defects that cannot be reconstructed properly by other methods. Although patients with an advanced hypopharyngeal cancer usually have a poor prognosis, this technique allows a better quality of life for a probable short life span.

Association of plasma triglyceride-rich lipoprotein remnants with coronary atherosclerosis in cases of sudden cardiac death

Among the risk factors for coronary atherosclerosis, elevated LDL-C level is best known. The action of lipoprotein lipase on triglyceride-rich lipoproteins produces remnant lipoprotein particles enriched in cholesterol and apolipoprotein E (apo E). Apo E serves as the ligand for uptake of remnant lipoproteins via the LDL-receptor or the remnant receptor. In this study, postmortem plasma total cholesterol, triglycerides (TG), VLDL-C, HDL-C, lipoprotein (a) [Lp(a)] and remnant-like lipoprotein particles (RLP)-cholesterol, RLP-TG, apolipoproteins B, C III and E were measured, together with LDL-C to assess their potential contribution to the severity of coronary and aortic atherosclerosis of the 197 cases of sudden death (132 cardiac death and 65 non-cardiac death). In all cases, the severity of coronary atherosclerosis was determined at postmortem pathological examination. RLP-cholesterol (RLP-C) and LDL-C concentrations were significantly higher in cases with advanced coronary atherosclerosis compared with those without coronary atherosclerosis; respective median values were 13.5 vs 8.4 mg/dl (P < 0.001) and 140 vs 115 mg/dl (P < 0.05). RLP-C levels were more strongly correlated with the severity score of coronary atherosclerosis than LDL-C.

Effect of 5-fluorouracil on gastrointestinal carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats

This study was undertaken to determine the effect of 5-fluorouracil on gastrointestinal carcinogenesis. Sixty rats were divided into three groups of 20 rats each. All rats were exposed to N-methyl-N'-nitro-N-nitrosoguanidine for the first 20 weeks. Group 1 rats received intraperitoneal injections of 5-fluorouracil for the first 20 weeks and were then observed for the second 20 weeks. Group 2 rats also received 5-fluorouracil injections, but for the second 20 weeks. Group 3 rats received no 5-fluorouracil treatment. Four of 20 rats in group 1 developed an invasive adenocarcinoma. In group 3, invasive squamous cell carcinoma and adenocarcinoma developed in one rat each. None of the group 2 rats had malignant lesions. These results suggested that 5-fluorouracil is not effective in suppressing the initial stage of gastrointestinal carcinogenesis with a coexisting carcinogen. Rather, the therapeutic effect is exerted in later stages of tumor progression.

Location of the femoral head in developmental dysplasia of the hip: three-dimensional evaluation by means of magnetic resonance image

By using magnetic resonance imaging, we analyzed the position of the femoral head in 21 hips of 21 infants with developmental dislocation. The femoral head changed its location according to the hip position. In type A dislocation, the head was anterior to the acetabulum when the hip was extended, and it was posterior when the hip was flexed. There was wide contact area between the femoral head and the acetabulum in any hip position. In type B, the head was on the rim of the acetabulum when the hip was extended. When the hip was flexed, the head was on the posterior rim of the acetabulum, and there was no contact between the femoral head and acetabular cartilage. Some heads slipped into the socket with a click phenomenon when the hip was flexed/abducted. In type C dislocation, the head was on the edge of the acetabulum when the hip was extended. When the hip was flexed, the head moved posteriorly, and it was completely out of the socket.

Complete dissection of the lymph nodes located along and at the roots of the left gastroepiploic vessels during distal gastrectomy

Achieving complete dissection of the lymph nodes located at the roots of the left gastroepiploic vessels is difficult when distal gastrectomy is the surgical goal; firstly, because the short gastric vessels must be preserved to supply blood to the remnant stomach; and also, because the roots of the left gastroepiploic vessels at the splenic hilus are obscured intraoperatively by adipose tissues. We describe herein a technique which enables complete and easy dissection of the lymph nodes located along and at the roots of the left gastroepiploic vessels.

Quantitation of herpes simplex viral DNA in Vero cells for evaluation of an antiviral agent using the polymerase chain reaction

A method for quantitation of the DNA of Herpes simplex virus type 2 (HSV-2)-infected Vero cells by the polymerase chain reaction (PCR) was developed. This method allowed recognition of several molecules of viral DNA among the total DNA extracted from cells. The method could be applied to a very large range (10(-0)-10(-7)) of initial amounts of template. Products of PCR were collected after each cycle for kinetic analysis. Products were subjected to electrophoresis and amplified bands were stained with ethidium bromide. The intensity of fluorescence of each band was measured with a charge-coupled device (CCD) image analyzer. The time course of increases in the relative yield of viral DNA was determined. Two-fold amplification of viral DNA occurred each 6-h cycle from 7 h after infection. Using this method, the yields of viral DNA after treatment with the drug acyclovir (ACV) at 0.1 and 2 microg/ml were about 1/10 and 1/80 of those from nontreated infected cells, respectively. These results indicate that this method makes clear the inhibitory effect of ACV on the synthesis of viral DNA.

Effect of cation-exchange pretreatment of aqueous soil extracts on the gas chromatographic-mass spectrometric determination of nerve agent hydrolysis products after tert.-butyldimethylsilylation

The efficiency of pretreatment of aqueous soil extracts using a cation-exchange resin has been investigated by gas chromatographic-mass spectrometric (GC-MS) determination of nerve agent hydrolysis products after tert.-butyldimethylsilyl (TBDMS) derivatization. An aqueous solution containing methylphosphonic acid (MPA) and its monoalkyl esters, ethyl methylphosphonic acid, isopropyl methylphosphonic acid and pinacolyl methylphosphonic acid, was dried, and these phosphonic acids were derivatized with N-methyl-N-(tert.-butyldimethylsilyl)trifluoro-acetamide and analyzed by GC-MS. The yields of TBDMS derivatives were significantly decreased by the addition of calcium and magnesium ions to an aqueous solution (approximately 0.5 mM) before derivatization. The extent of lowered yields was related to the hydrophilicity of phosphonic acids. MPA and its monoalkyl esters were spiked into soil samples (sand, alluvial soil and volcanic ash soil), extracted with distilled water, dried, silylated and applied to GC-MS. The yields of TBDMS derivatives of monoalkyl esters from soil samples were low (3-42%) and MPA derivative was scarcely detected (yield: < 0.7%). By desalting the aqueous soil extract by passage through a strong cation-exchange resin, the yields of TBDMS derivatives of monoalkyl esters were significantly improved (12-69%) and MPA derivative was detected (yield: 2-36%). The extent of improved yields was related to the concentrations of divalent metal cations in aqueous soil extracts. In combination with desalting by the cation-exchange resin, GC-MS after TBDMS derivatization enables detection of nerve agent hydrolysis products in soils at sub-ppm (0.2 microgram/g) concentrations.