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Biomedical subjects

M Jones

Publications and source records attributed to M Jones.

At least 1,009 records · Page 56Linked to original sources
PubMedDate not supplied

Endoscopic needle aspiration biopsy at ERCP in the diagnosis of biliary strictures.

We have developed a ball-tipped catheter with a retractable 22-gauge, 7-mm long needle to perform endoscopic needle aspiration (ENA) for cytology and compared this technique to brush cytology of malignant-appearing biliary strictures during ERCP. Of 31 patients, 26 had proven malignant strictures involving the common bile duct and 5 had benign lesions. All 31 patients had ENA and 29 were brushed. Positive ENAs were obtained in 16 of 26 patients (61.5%) and positive brushings in 2 of 24 (8.3%). With the addition of two suspicious ENAs for pancreatic adenocarcinoma, 73% of patients had positive or suspicious cytology for malignancy by combined ENA and brush with a specificity of 100%. Although ENA appeared to be more sensitive in diagnosing cholangiocarcinoma, it proved to be most effective in the diagnosis of pancreatic adenocarcinoma when compared with brush cytology. One patient with cholangiocarcinoma in our series was diagnosed by brush cytology only, with a negative ENA, supporting our recommendation of using both endoscopic brushings and ENA for cytology when evaluating biliary strictures.

Adenocarcinoma↗
PubMedDate not supplied

Processing of mispaired and unpaired bases in heteroduplex DNA in E. coli.

Bacteriophage lambda and phi X 174 DNAs, carrying sequenced mutations, have been used to construct in vitro defined species of heteroduplex DNA. Such heteroduplex DNAs were introduced by transfection, as single copies, into E. coli host cells. The progeny of individual heteroduplex molecules from each infective center was analyzed. The effect of the presence of GATC sequences (phi X 174 system) and of their methylation (lambda system) was tested. The following conclusions can be drawn: some mismatched base pairs trigger the process of mismatch repair, causing a localized strand-to-strand information transfer in heteroduplex DNA: transition mismatches G:T and A:C are efficiently repaired, whereas the six transversion mismatches are not always readily recognized and/or repaired. The recognition of transversion mismatches appears to depend on the neighbouring nucleotide sequence; single unpaired bases (frameshift mutation "mismatches") are recognized and repaired, some equally efficiently on both strands (longer and shorter), some more efficiently on the shorter (-1) strand; large non-homologies (about 800 bases) are not repaired by the Mut H, L, S, U system, but some other process repairs the non-homology with a relatively low efficiency; full methylation of GATC sequences inhibits mismatch repair on the methylated strand: this is the chemical basis of strand discrimination (old/new) in mismatch correction; unmethylated GATC sequences appear to improve mismatch repair of a G:T mismatch in phi X 174 DNA, but there may be some residual mismatch repair in GATC-free phi X 174, at least for some mismatches.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteriophage lambda↗
PubMedDate not supplied

Quantification of mitral flow by Doppler color flow mapping.

This study was performed to develop and validate Doppler color flow methods for quantifying forward transmitral flow rates and volumes with isovelocity aliasing contours. We undertook computer modeling of flows and studied an animal model with strictly controlled mitral flows. Finite element analysis was first used to establish the isovelocity surface contours reconstructed from the magnitudes and directions of the velocity vectors proximal to the normal mitral orifice. We modeled finite element-simulated Doppler color flow isovelocity surfaces and computed non-angle-dependent simulated isovelocities to compare them. Then 24 pharmacologically induced hemodynamic states in six sheep in which mitral regurgitation had been previously created surgically were studied. Three methods were used for peak flow (PF) computation: (1) the classic hemispheric methods: PF = 2 pi r2.aliasing velocity; (2) a modified hemispheric method: PF = 2 pi r2.aliasing velocity Vo/Vo-aliasing velocity; and (3) a new segment of sphere method: PF = pi p2.aliasing velocity, where p is the chord from the zenith of the first aliasing contour to the circumference at its base. Mean volume flow was also calculated in combination with phasic flow information from continuous-wave Doppler echocardiography: mean volume flow = PF.VTI/Vmax.heart rate, where VTI and Vmax are the velocity-time integral and maximal velocity of mitral inflow by continuous-wave Doppler echocardiography. Compared with the flow rates obtained by electromagnetic flowmeters, different correlations and agreements were achieved for these methods. Correlation (r = 0.86) and agreement were best for the segment of sphere method for computation of forward mean volume flows in our model. Color flow Doppler quantitation with a segment of sphere or modified hemispheric method appears applicable for quantification of forward transmitral valve flow rates and volumes with reasonable accuracy.

Animals↗
PubMedDate not supplied

The DNA sequence and comparative analysis of human chromosome 20.

The finished sequence of human chromosome 20 comprises 59,187,298 base pairs (bp) and represents 99.4% of the euchromatic DNA. A single contig of 26 megabases (Mb) spans the entire short arm, and five contigs separated by gaps totalling 320 kb span the long arm of this metacentric chromosome. An additional 234,339 bp of sequence has been determined within the pericentromeric region of the long arm. We annotated 727 genes and 168 pseudogenes in the sequence. About 64% of these genes have a 5' and a 3' untranslated region and a complete open reading frame. Comparative analysis of the sequence of chromosome 20 to whole-genome shotgun-sequence data of two other vertebrates, the mouse Mus musculus and the puffer fish Tetraodon nigroviridis, provides an independent measure of the efficiency of gene annotation, and indicates that this analysis may account for more than 95% of all coding exons and almost all genes.

Animals↗
PubMedDate not supplied

Scleroderma in South Australia: epidemiological observations of possible pathogenic significance.

BACKGROUND: Scleroderma is an autoimmune disorder of unknown cause. Previous epidemiological studies have suggested some regional clustering and associations with occupations involving exposure to silica dusts and hydrocarbons. AIMS: To determine: (i) prevalence and incidence of scleroderma in South Australia (SA), a state with a stable population living in well-defined urban, rural and industrial regions, (ii) hospital separation rates, (iii) cumulative survival rates, (iv) gender and disease subclassification, (v) geographical residency and occupations, (vi) familial associations and (vii) age at onset versus age-specific incidence rate. METHODS: Creation of the South Australian Scleroderma Register (SASR) to identify demographics and clinical and serological features of all scleroderma patients resident in SA. RESULTS: Scleroderma occurs in South Australia with a point prevalence of 23 per 10(5) and an incidence of approximately 1/15th of this. However, this prevalence is high compared with other regional world studies. Scleroderma is predominantly a female disease, with most patients having the limited form of scleroderma characterized by the presence of the anticentromere antibody and a mean survival of 27.6 years. In contrast, diffuse scleroderma is a less benign disease occurring at an early age of onset and has a mean survival of 9.6 years. Scleroderma occurs throughout SA without regional localization. Weak associations are seen in males, but not females, with occupations involving possible environmental exposure to silica or hydrocarbons. Scleroderma rarely occurs in families. CONCLUSION: No strong genetic or environmental influences were found to account for the relatively common occurrence of scleroderma in SA. The age at onset versus age-specific incidence curve suggests that scleroderma can be considered as a stochastic illness involving a number of random events occurring in a predisposed population. These random events may involve mutations of pivotal somatic genes.

Age of Onset↗
PubMedDate not supplied

Mortality and industrial hygiene study of workers exposed to polychlorinated biphenyls.

Because of the demonstrated toxic effects on animals resulting from exposure to polychlorinated biphenyls (PCBs), the National Institute for Occupational Safety and Health conducted a retrospective cohort mortality study of 2,567 workers in two plants where PCBs were used in the manufacture of electrical capacitors. All workers included in the study were employed for at least 3 months in areas of the plants where PCBs were used. The vital status of 98% of the two cohorts was determined, and 39,018 person-years were accumulated. All-cause mortality was lower than expected (163 obs. vs 182.4 exp.) as well as all cancer mortality (39 obs. vs 43.8 exp.). Excess mortality was noted for rectal cancer (4 obs. vs 1.19 exp.) and liver cancer (3 obs. vs 1.07 exp.), although neither excess was statistically significant. In one of the plants the observed mortality due to cirrhosis of the liver was also elevated. The results of detailed industrial hygiene surveys conducted in each plant are also presented.

Female↗
PubMedDate not supplied

Cardiopulmonary bypass through peripheral cannulation with percutaneous decompression of the left heart in a model of severe myocardial failure.

Prolonged closed chest cardiopulmonary bypass for severe total biventricular myocardial dysfunction requires invasive decompression of the left heart. The authors have developed an elongated helical coil that is permanently attached to the distal 8-10 cm of a flow directed Swan-Ganz catheter. When properly positioned, the helical coil kept the pulmonary artery (PA) and the tricuspid valves open, and allowed closed chest retrograde decompression of the left heart. The authors have evaluated the merits of closed chest cardiopulmonary bypass with decompression of the left heart in this manner in four sheep subjected to 30 min of warm global myocardial ischemia, along with induced ventricular fibrillation. All sheep developed severe global myocardial failure, with no left ventricular (LV) ejection. The authors have shown that pulmonary blood flow during cardiopulmonary bypass was reversed from the left heart, across the lungs, and into the right heart. The wedge pressure never exceeded 12 mmHg at any time, attesting to good decompression during periods of total ventricular failure, during partial recovery with some LV ejection, and after good recovery of LV function, followed by weaning from bypass after 44, 67, and 78 h of such support. One sheep could not be weaned from bypass, even after 5 days of CPBP. Lung function in all sheep remained unimpaired throughout, and there was no wound bleeding. The authors conclude that in this model of total myocardial failure, and while on closed chest CPBP, at all times and with all degrees of myocardial dysfunction, excellent LV decompression with the helical coil catheter was attained.

Animals↗
PubMedDate not supplied

Microsporidiosis in a Gouldian finch (Erythrura [Chloebia] gouldiae).

A 12-day-old nestling Gouldian finch (Erythrura [Chloebia] gouldiae) was presented for investigation of a mortality problem in nestling finches raised by Bengalese finch foster parents. On histological examination, large numbers of spores consistent with a microsporidian organism were present within the small intestinal mucosa. Electron microscopy and molecular studies (sequencing the 5' end of the ssu rRNA gene) further defined the organism as Encephalitozoon hellem. Sequence homology with other eukaryotes was determined using a BLASTN search from the NCBI GenBank database. The finch isolate sequences showed greater than 99% homology with those of previously reported human and avian isolates.

Animals↗
PubMedDate not supplied

Effect of CO2 inhalation on central sleep apnea and arousals from sleep.

BACKGROUND: CO(2) inhalation reduces central sleep apnea (CSA) in patients with congestive heart failure (CHF) and idiopathic CSA. CO(2) is also a stimulus for cortical arousal, which has been linked to increased sympathetic nerve activity (SNA) and increased mortality in CHF patients with CSA. OBJECTIVE: We have tested the hypothesis that during sleep, inhalation of CO(2) sufficient to reduce the apnea-hypopnea index (AHI) would not reduce the arousal index (AroI). METHODS: In 10 male patients with CSA (7 with CHF and 3 with idiopathic CSA), the inspired CO(2) concentration was increased to raise the sleeping end-tidal CO(2) by 2-4 mm Hg during established stage 2 sleep. Each intervention was maintained for a 10-min period. Sleep stage was monitored with electroencephalograms, electrooculograms, submental electromyogram, airflow with pneumotachometer and respiratory effort and blood gases with oxygen saturation and end-tidal CO(2). During periods of air and CO(2) breathing, AHI and AroI were compared with paired t tests; patients acted as their own controls. RESULTS: Inhalation of CO(2) produced a significant reduction in AHI (mean +/- SEM) from 74.4 +/- 12.4 events/h during air breathing to 25.8 +/- 7.8 events/h with CO(2) inhalation (p = 0.002). However, the AroI was not significantly different between the two conditions, air 67.8 +/- 12.3 events/h and CO(2) inhalation 52.8 +/- 12.4 events/h (p = 0.264). CONCLUSION: CO(2) inhalation reverses CSA but not arousals from sleep. Our findings highlight the need for treatment options that reduce both respiratory events and decrease arousals from sleep, with their associated SNA sequelae.

Administration, Inhalation↗
PubMedDate not supplied

Percutaneous endoscopic vs surgical gastrostomy.

The percutaneous endoscopic gastrostomy (PEG) has replaced the surgical gastrostomy (GT) on our service. We reviewed our data in an effort to determine relative efficacy and cost effectiveness of the two techniques. Thirty-five patients with PEGs were matched for age and diagnosis with 35 patients with GTs done by the same surgical service. PEGs were done in the endoscopy suite; GTs were done in the operating room: both under local anesthesia. Patients in PEG and GT groups were comparable in sex, diagnosis, and age. The PEG took less time to insert (15.3 vs 25.4 min, p less than 0.001). Major postoperative morbidity was similar with 10 systemic complications for each group and 11 deaths for the PEG vs 12 deaths for the GT group (at 90 days). Minor morbidity was higher for the PEG group with nine complications vs 1. Estimated cost for PEG was half the cost of GT. Hospital stay for the two groups was similar (36 vs 45 days, p greater than 0.1), but postop stay for the PEG group tended to be shorter (17 vs 24 days, p less than 0.08). The PEG is faster and cheaper to insert than the GT, however major morbidity and mortality are the same.

Anesthesia, General↗
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Testing for HIV antibody: a comparison of two services offered in a genitourinary medicine clinic.

Rates of screening for sexually transmissible infections in patients using different services provided by a genitourinary medicine clinic for testing for HIV antibodies are presented. Those patients whose primary reason for attending the clinic was HIV antibody testing and used the same day result (SDR) service were significantly less likely to be screened for other infections than those using the normal waiting time (NWT) service, (P < 0.00001). This was true for both males and females. Of those patients screened for other infections in the SDR and NWT groups 29% and 35% respectively were found to have a sexually transmitted infection. It would appear that an SDR service offers little benefit for the majority of patients as only a few patients would not have had an HIV antibody test had the SDR not been available.

AIDS Serodiagnosis↗
PubMedDate not supplied

Intraosseous ganglion cyst of the talus: case report.

A case of an intraosseous ganglion cyst of the talus is described. Ganglion cysts within bone are not rare but are usually found within long bones located in metaphyseal areas. This lesion of the talus produced significant pain and was successfully treated with curettage and iliac crest bone graft.

Adult↗