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Biomedical subjects

J Robinson

Publications and source records attributed to J Robinson.

At least 613 records · Page 34Linked to original sources
PubMedDate not supplied

Scrotal hypothermia and testicular blood flow in the dog. Absence of thermal regulation.

Two clinically tolerable methods of producing testicular hypothermia have been studied in dogs. Evaporative cooling produced a 3.7 degree fall and ice water a 9.7 degree fall in intratesticular temperatures. Scrotal skin blood flow (mls/100 gm/min) fell from 4.9 +/- 4.6 to 2.3 +/- 1.2 and 1.3 +/- .05 with the two techniques and was associated with increased vascular resistance. In contrast, no significant change was noted in testicular blood flow. These data show that testicular blood flow cannot be altered by clinically tolerable hypothermia.

Animals↗
PubMedDate not supplied

Myosin autoantibodies reacting with selective muscle fiber types.

Myosin in striated muscle exists in at least two immunologically distinct forms. Human autoantibodies specific for either form show selective muscle fiber reactivity. One group of antibodies reacts with type 2b (white) muscle fibers, the other with type 2a (red) and type 1 (intermediate) fibers. All of these antibodies react with the A band of glycerinated myofibrils. Both groups of antibodies react with cardiac muscle. Muscle-fiber-specific antibodies are detected in approximately 1% of sera submitted for diagnostic screening. Sera from eight patients were studied further. The two patients with antibodies against type 2b (white) muscle myosin had rheumatoid arthritis. The six patients with antibodies against type 2a (red) and type 1 (intermediate) myosin had clinical features which included various autoimmune and infectious disorders.

Animals↗
PubMedDate not supplied

Application of red cell distribution width to screening for coeliac disease in insulin-dependent diabetes mellitus.

Coeliac disease has been reported to occur in 2-5 per cent of insulin-dependent diabetic patients (IDDM). Suitable non-invasive screening tests would allow identification of these patients. The aim of this study was to determine the value of the red cell distribution width (RDW) in detecting unrecognised coeliac disease in insulin-dependent diabetic patients (IDDM). All patients (n = 208) attending the Diabetic out-patient clinics at 2 adjacent centres who had a full blood picture and RDW carried out in the past 18 months were included. IDDM patients with an elevated RDW were identified and their charts were reviewed to determine if they had symptoms or laboratory abnormalities compatible with coeliac disease. They were invited to attend for serological screening. Ninety-five of 208 patients had an elevated RDW of whom 66 had non-insulin dependent diabetes mellitus and 29 had IDDM. Two of the 29 IDDM patients had died in the interim period. Six of the remaining 27 IDDM patients had previously been tested for serological markers associated with coeliac disease, of whom 1 had a positive antigliadin antibody titre (IgA-AGA 199 EU) and normal duodenal biopsy. Eighteen of the remaining 21 patients with IDDM consented to serological testing of whom only 1 had a positive titre of antiendomysial antibody (IgA-EMA) and villous atrophy. Although the RDW is known from previous studies to be a sensitive predictor for coeliac disease, this study has demonstrated its poor specificity in predicting IDDM patients who may have coeliac disease. The RDW is not recommended as a screening test for coeliac disease in patients with IDDM.

Celiac Disease↗
PubMedDate not supplied

Spirochetes: vaccines, animal models and diagnostics.

The detailed characterization of various proteins from spirochetes using molecular biology techniques has made possible new approaches to vaccine and diagnostic development that are described in this session. The importance of animal models was emphasized and illustrated.

Animals↗
PubMedDate not supplied

Chloride channels of high conductance in the microvillous membrane of term human placenta.

The patch clamp technique has been used to study ion channels in the undisturbed microvillous membrane of the human placental syncytiotrophoblast. In villi from 55 placentae delivered by caesarean section, high resistance seals were achieved in approximately 30 percent of attempts. Of these, a large conductance chloride channel was identified in seven inside-out and two 'cell' attached patches. The channel had the following properties: (a) a slope conductance of 313 +/- 9 pS, (b) the presence of sub-conductance states, (c) voltage dependency, being open predominantly between +/- 20 mV and inactivating at more extreme potentials and (d) inhibition by DIDS (4-acetamido-4'-diisothiocyanostilbene 2,2-disulphonic acid). These are characteristic features of 'maxi' chloride channels which have been identified in a variety of cell types (Gogelein, 1988). The role of the chloride channel in ion transport by or homeostasis of the syncytiotrophoblast has yet to be determined.

Chloride Channels↗
PubMedDate not supplied

Temporal and spatial patterns of opsin gene expression in zebrafish (Danio rerio).

In zebrafish, the first class of cone photoreceptor to become morphologically distinct is the ultraviolet-sensitive short single cone, at 4 days postfertilization, whereas the last class, the red- and green-sensitive double cone, becomes distinct at 10 days postfertilization. We have examined the time course of visual pigment gene expression in zebrafish using whole-mount in situ hybridization. Within the retina, opsins may be detected as early as 40 h postfertilization with the ultraviolet and rod visual pigments being expressed before the blue- (48 h) and red- (60 h) sensitive pigments. In the pineal, red-sensitive opsin is expressed at 48 h postfertilization. Visual pigment expression provides a useful tool for investigations of early cell fate in zebrafish.

Animals↗
PubMedDate not supplied

Sugar recovery and fermentability of hemicellulose hydrolysates from steam-exploded softwoods containing bark.

The hemicellulose sugar recovery and ethanol production obtained from SO2-catalyzed steam explosion of a mixed white fir (70%) and ponderosa pine (30%) feedstock containing bark (9% dry weight/dry weight) was assessed. More than 90% of the available hemicellulose sugars could be recovered in the hydrolysate obtained after steam explosion at 195 degrees C, 2.38 min, and 3.91% SO2, with 59% of the original hemicellulose sugars detected in a monomeric form. Despite this high sugar recovery, this hydrolysate showed low ethanol yield (64% of theoretical yield) when fermented with a spent sulfite liquor-adapted strain of Saccharomyces cerevisiae. In contrast, most hydrolysates prepared at higher steam explosion severity showed comparable or higher ethanol yields. Furthermore, the hydrolysates prepared from bark-free feedstock showed better fermentability (87% of theoretical yield) despite containing higher concentration of known inhibitors. The ethanol yield from the hydrolysate prepared from a bark-containing wood sample could be improved to 81% by an extra stage acid hydrolysis (121 degrees C for 1 h in 3% sulfuric acid). This extra stage acid hydrolysis and steam explosion at higher severity conditions seem to improve the fermentability of the hydrolysates by transforming certain inhibitory compounds present in the hydrolysates prepared from the bark-containing feedstock and thus lowering their inhibitory effect on the yeast used for the ethanol fermentation.

Abies↗
PubMedDate not supplied

Studies on the blood of a Co (a-b-) proposita and her family.

The serum of a pregnant woman whose red cells typed as Co(a-b-) contained an alloantibody that, at the time of the infants delivery, was hemolytic in vitro and had a titer of 32,000 by the antiglobulin test. This antibody, which reacted with cells of all Colton-phenotypes except the proposita's own cells, showed very weak reactions with other Co(a-b-) cells and therefore cannot be called anti-Co3. The red cells of the proposita may carry a very weak Co3 antigen. No other persons of the Co(a-b-) phenotype were found in her members, among three of the four generations tested, suggested that an inhibitor gene may be responsible for the unusual Colton phenotypes in this family. The proposita's infant required one exchange transfusion with red cells obtained from the proposita. Red cells from 40,000 donors reacted with the serum of the proposita.

Adult↗
PubMedDate not supplied

Uterine junctional zone contractions during assisted reproduction cycles.

This study was designed to assess junctional zone contractions (JZ) during cycles of in-vitro fertilization (IVF) and embryo transfer in oocyte donors exposed to a long protocol regime for ovarian stimulation. Real-time transvaginal ultrasound and advanced audio-visual and computer technology were used to evaluate the contraction pattern, frequency and velocity. At the time of down-regulation JZ contractions were not observed. After 7 days of superovulation all patients displayed cervico-fundal, fundo-cervical and random contractions. Cervico-fundal waves dominated the picture at the time of human chorionic gonadotrophin injection. However, the activity was strongest on the day of oocyte retrieval. At that time the percentage of opposing waves increased and fundo-cervical waves disappeared. The highest wave frequency and velocity (4.29+/-0.68 waves/min and 2.73+/-0.54 mm/s respectively) were observed at the time of oocyte retrieval. All patients had some JZ activity on days 2, 3 and 4 after oocyte retrieval but regular wave-like contractility gradually decreased and only single random movements were seen on day 4 after oocyte retrieval. In conclusion, JZ activity throughout the IVF cycle is more exaggerated when compared to the results reported from observations of the natural cycle but follows a similar pattern. This fact can probably be explained by the vastly different hormone levels. Higher JZ activity and correspondingly increased mobility of the endometrium may impair its receptivity and affect implantation.

Adult↗
PubMedDate not supplied

The effect of diagnostic radiopaque fluids used in discography on chymopapain activity.

It has been thought that intradiscal injection of radioopaque fluids prior to intradiscal chymopapain therapy might have some inhibitory effect on its enzyme activity and, thus, disc nuclear dissolution. This raised the question--what interval should elapse between discography and injection of the chymopapain to avoid this possible effect? The effects of Hypaque (Conray), metrizamide, and Urografin on chymopapain activity were measured. The most suitable substrate was N. Benzoyl-DL-arginine paranitroanilide (BAPNA). The yellow p-nitro aniline liberated (a measure of the enzymic activity of chymopapain) was determined by absorption spectrometry. Controlled series using 1) Hypaque plus substrate plus no enzyme, 2) Hypaque, enzyme, no substrate, and 3) Hypaque plus substrate plus enzyme showed no action. Hypaque (Conray) and Urografin are seen to enhance enzymic action of chymopapain. Metrizamide has slight inhibitory action. Effects of Dimerex were variable. Weak Hypaque increases activity (20%); 100% solution doubles activity. Thus, there is no necessity to delay injection of enzyme after Hypaque, Conray, Urografin, especially as disc radioopacity can persist up to 24 hours. Prior injection of 95% alcohol (as used by Trosier) abolishes chymopapain activity.

Chymopapain↗
PubMedDate not supplied

Infected aluminum oxide orbital implant.

Porous orbital implant infection is rare. The diagnosis may be delayed as the initial symptoms and signs are not always indicative of implant infection. It is often only with time, a persistence of symptoms and signs, and additional symptoms and signs that implant infection is suspected.

Aluminum Oxide↗
PubMedDate not supplied

Potassium-sparing effect of amiloride in a diuretic factorial study in man.

1. The effects of amiloride (M, 20 mg/day), chlorothiazide (C, 1000 mg/day), ethacrynic acid (E, 100 MG/day) and frusemide (F, furosemide 80 mg/day, given alone and in combination, were investigated in eight patients in a 2(4) factorial study. Effects between blocks of four treatments in each sixteen-treatment replicate were confounded with higher interactions to allow for differences between early and late diuresis. 2. All patients exhibited marked diuresis, with significant mean increases in daily urinary sodium excretion (P smaller than 0.05) and urinary volume (P smaller than 0.01) induced by chlorothiazide, frusemide and ethacrynic acid (68, 69 and 38%; and 35, 40 and 34%, respectively). Amiloride appeared to be half to one-third as potent as the other diuretics. 3. Amiloride produced a significant potassium-sparing effect (P smaller than 0.01), reducing urinary potassium excretion by 30%, compared to significant urinary potassium wasting with frusemide (increase of 33%, P smaller than 0.01) and chlorothiazide (increase of 31%, P smaller than 0.05). 4. No adverse reactions occurred, but serum potassium levels twice rose to 6 mmol/l and subsided without additional therapy, and on one occasion fell to 2.5 mmol/l, requiring a potassium supplement for 4 days. 5. It was concluded from these factorial studies that amiloride is a mild diuretic and potent potassium-sparing agent acting independently and additively in combination with chlorothiazide, ethacrynic acid or frusemide. For the three latter diuretics, all two-drug interactions were simply additive also, without evidence of synergism or antagonism between drugs.

Amiloride↗