Biomedical subjects
A Ram
Publications and source records attributed to A Ram.
A study of aluminum phosphide (AlP) poisoning with special reference to electrocardiographic changes.
Ninety patients with aluminum phosphide poisoning have been studied over a period of 3 years. Epigastric pain and vomiting were the common initial clinical features, followed 12 to 24 hours later by cardiogenic shock, oliguria, altered mental state and respiratory distress. Death occurred within 24 to 72 hours presumably due to poison-induced toxic chemical myocarditis as reflected by electrocardiographic changes. The overall mortality was 63.3%. Intravenous magnesium sulphate, probably due to its membrane stabilizing action, appears to be related to the reduction in mortality from 90% to 52% in the latter 62 cases.
Serotonin 5-HT2 receptor binding on blood platelets--a peripheral marker for depression?
Several methods of platelet membrane preparation and binding conditions were screened in order to optimize the labeling of serotonergic 5-HT2 receptors on previously frozen human platelet membranes with tritiated ketanserin. Under optimal conditions, 5-HT2 receptors in normal subjects (5 males, 7 females, age range 21 to 71) have a Kd of 1.5 +/- 0.2 nM and a Bmax of 33.9 +/- 5.3 fmole/mg protein. In a group of patients with major depressive disorder exactly matched for age and sex with the normal control group, we find a significant increase in receptor density, to 66.8 +/- 11.4 fmole/mg, with no significant change in the affinity (2.3 +/- 0.5 nM). Four weeks of treatment with antidepressant drugs result in a significant decrease of Bmax, down to control levels (29.4 +/- 3.9). Thus, ketanserin can be used to monitor changes in platelet serotonin 5-HT2 receptors which may be a relevant marker for the state of depression.
Bilateral floating knees in a multiple injured patient. A case report.
Bilateral floating knees are rarely seen in orthopedic practice. Ipsilateral fractures of the femur and tibia are becoming more common due to an increase of high-velocity accidents. The following case presents a 23-year-old male motorcyclist who sustained multiple musculoskeletal injuries including a burst fracture of the elbow and fractures of both femurs and both tibiae. Early operative stabilization of all the fractures was performed. A comminuted fracture of the ulna was fixed with a Dynamic Compression Plate (DCP) and the fractures of both femurs and both tibiae were fixed with Enders nailing. Operative treatment produced excellent results without significant complications. As a result of this study it is concluded that Enders nailing of long bone fractures is a useful procedure in selected patients and can produce desirable results.
[Dexamethasone suppression test in psychiatrically hospitalized adolescents].
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Synovial biopsy in osteoarticular tuberculosis.
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Cyclic variations in the permeability of the cell wall of Saccharomyces cerevisiae.
To study cell-cycle-related variations in wall permeability of Saccharomyces cerevisiae, two approaches were used. First, an asynchronous culture was fractionated by centrifugal elutriation into subpopulations containing cells of increasing size. The subpopulations represented different stages of the cell cycle as judged by light microscopy. Cell wall porosity increased when these subpopulations became enriched with budded cells. Secondly, synchronous cultures were obtained by releasing MATa cells from alpha-factor induced G1-arrest. These cultures grew synchronously for at least two generations. The cell wall porosity increased sharply in these cultures, shortly before buds became visible and was maximal during the initial stages of bud growth. It decreased in cells which had completed nuclear migration and before abscission of the bud had occurred. The porosity reached its lowest value during abscission and in unbudded cells. We examined the incorporation of mannoproteins into the wall during the cell cycle. SDS-extractable mannoproteins were incorporated continuously. However, the incorporation of glucanase-extractable mannoproteins, which are known to affect cell wall porosity, showed cyclic oscillations and reached its maximum after nuclear migration. This coincided with a rapid decrease in cell wall porosity, indicating that glucanase-extractable mannoproteins might contribute to this decrease.
Prospects for application of post-consumer used plastics in food packaging.
The two most widely used polymers in packaging in recent years are polyethylene terephthalate (PET) and polyethylene (PE). The biggest fractions of these polymers are not re-utilized, in spite of the fact that they possess excellent properties even after their first application. The ban on using recycled polymers in food packaging applications and the lack of good value outlets for these materials causes them to end up in landfills. The high cost nylon, used in packaging primarily as high gas barrier laminates with PE, also finds its way to landfills. In this case, the reason is the difficulty of recycling different polymers that are incompatible. Thus, the Municipal Solid Waste (MSW) stream transferred to landfills contains many plastic packages. These packages are being blamed as a major pollutant of the environment in spite of the fact that all plastics contribute only a small percentage to the weight of the garbage in landfills. If proper and cost effective applications for the recycled polymers could be developed, the waste related to their disposal could be limited. In addition, the contribution of plastic packages to the environmental problem could be diminished. In the present paper, the possibility of sandwiching a contaminated PET layer between two layers of the virgin material was studied. The aim of the study was to determine whether such an operation could lower the migration level of contaminants from a multilayer structure (containing a recycled layer of PET) to values below the limits required by regulatory agencies. The diffusion coefficients (required to determine migration) of four organic liquids in PET were determined. As a result of the sandwiching operation, the amount of pollutant (toluene) migrating into the food simulant was reduced by two orders of magnitude. The properties of PE/nylon blends were also studied. It was found that the high gas barrier properties of nylon are preserved in the blend when proper processing conditions are used. Therefore, the recycled material could be used as a centre layer in a multilayer structure providing good gas barrier properties to this structure.
Problem solving, contention, and struggle: how siblings resolve a conflict of interests.
In a laboratory setting, 48 sibling dyads age 4 and 6 or 6 and 8 years negotiated the division of six toys. Findings revealed that, in general, children reached divisions while using a preponderance of constructive problem-solving strategies, rather than contentious tactics. The degree of conflict of interests and the quality of sibling relationships predicted the children's use of problem-solving and contentious negotiation strategies, and was related to the types of resolutions achieved. Dyads experiencing low conflict of interests resolved their differences quickly. High conflict of interests coupled with positive relationships and constructive negotiation resulted in longer negotiations and creative, agreeable resolutions. High conflict of interests coupled with more negative relationships and destructive negotiations resulted in children's failures to reach agreement. Developmental differences indicated that older siblings within the pairs took the lead in negotiation, and benefited slightly more from the divisions. Furthermore, children in older dyads were more sophisticated and other oriented in their negotiations.
Ventilatory response and pattern of breathing during hypercapnia.
In an attempt to narrow the definition of normal ventilatory response to hypercapnia (SVE), we studied 105 healthy Caucasians, aged from 18 to 80 years and living at sea level. The mean and SD of SVE were 2.18 +/- 0.77 1 X min-1 X mmHg-1 in males and 1.70 +/- 0.74 in females, narrower than the ranges previously reported. The 95% tolerance limits were 0.491-3.735 and 0.241-2.963 respectively. SVE was correlated with height, body surface area, static and dynamic lung volumes (p less than 0.01), age and weight (p less than 0.05). A prediction formula for SVE was derived on the basis of FEV1, which of the above parameters best correlated with SVE. The separate measurement of the tidal volume and frequency changes (SVT, Sf and SVT/Sf) showed that the SVT and SVT/Sf were significantly higher in males than in females even after adjustment for lung volume (p less than 0.01 and p less than 0.02 respectively), suggesting a different pattern of response to hypercapnia between the sexes.