Thymus-derived lymphocytes and their interactions with macrophages are required for the production of osteoclast-activating factor in the mouse

A bone-resorbing factor, comparable to the osteoclast-activating factor (OAF) produced from peripheral blood leukocytes, is shown to be produced by murine spleen cells activated with the T-cell mitogen Con A. Murine OAF is demonstrated here as being a product of the interaction between thymus-derived T lymphocytes and macrophages. Activation of T cells in the presence of macrophages with Con A yields culture supernatants with OAF activity. This OAF activity is not dialyzable and is not extracted by lipid solvents. Purified B cells in the presence or absence of macrophages and cocultured with Con A or activated with the B-cell-specific mitogen lipopolysaccharide yield culture supernatants with no detectable OAF activity. Similarly, macrophages cocultured with Con A or activated with lipopolysaccharide fail to yield culture supernatants with bone resorbing activity. These types of immune cell interactions are similar to that required for the production of lymphokines. These data support the hypothesis that one aspect of regulation of bone remodeling is through cells of the immune system.

Effect of plasma volume on thermoregulation in the dog

Panting thresholds, plasma volume (PV) changes and cardiac filling pressure were studied during thermal dehydration in control, water deprived (WD) and hypovolemic (PEG) dogs. WD and PEG dogs showed a delayed panting threshold, apparently due to hypovolevoia. Initiation of heat stress however resulted in a transient plasma expansion in all dogs. Cardiac filling pressure did not change.

Gastric emptying in normal subjects--a reproducible technique using a single scintillation camera and computer system

The gastric emptying of a mixed solid and liquid meal was assessed in 24 normal subjects using a single camera/computer system which allowed continuous monitoring of both solids and liquids. It was shown that variation in tissue attenuation caused by the changing depth of radionuclide within the stomach accounted for large errors in the measurement of gastric emptying (alteration in 50% emptying time of up to 65%). A technique for the correction of attenuation is described which used factors derived from a lateral image of the stomach. In all subjects, solid emptying was slower than liquid emptying and was characterised by a delay (lag period) which was followed by linear emptying. Liquid emptying usually followed a single exponential pattern. The effect of physiological changes induced by increasing the calorie content of the liquid component of the meal was assessed by giving either water, 10% dextrose or 25% dextrose. Liquid emptying was slowed and the lag period of solid was prolonged as the calorie content increased. Reproducibility was assessed in 19 subjects. For the three groups studied (water, 10% dextrose, 25% dextrose) the day-to-day variation in gastric emptying was not significant for any measured parameter, while statistically significant differences were present in solid and liquid emptying between subjects and groups.

The value of the autopsy in medical audit--a combined clinical and pathological assessment of 100 cases

We retrospectively reviewed 100 consecutive autopsies performed at the Royal Adelaide Hospital in 1979. The review was made jointly by a clinician, surgical pathologist and forensic pathologist. The mean patient age was 64.5 years. Sixteen percent of premortem anatomical diagnoses were not confirmed at autopsy. Autopsy revealed 171 new anatomical diagnoses. Of these, 33 diagnoses in 27 patients were important in relation to the cause of death and if known premortem would have altered therapy and possibly outcome in two patients. In 11 cases the missed major diagnoses should have been entertained on the basis of available clinical data. Of the 19 sudden deaths, the cause of death was not included in the clinical differential diagnosis in seven cases. Autopsy resulted in a substantial change in the death certification of 43 cases. The data indicate that the autopsy has a great deal to offer in correcting clinical diagnoses and effecting scientific discipline for clinicians.

Effect of high temperatures on imbibition, germination, and thermal death of velvetleaf (Abutilon theophrasti) seeds

Seeds of velvetleaf (Abutilon theophrasti Medic.) were treated for various durations at temperatures from 40 to 60 °C. Rate of water uptake increased with temperature of imbibition. Germination of imbibed (soft) seeds was not affected by 40 °C imbibition for 30 h. At temperatures ≥ 43 °C, an inverse relationship was seen between temperature and time of imbibition required to reduce germination by a given level. Seeds exposed to temperatures up to 55 °C in dry or humid air or imbibed in osmotica of polyethylene glycol 6000 showed inhibitory effects on germination increased as time of exposure and seed water content increased. Seeds with low water content required longer exposures or higher temperatures to reduce germination. Heat treatments of <2 h caused greater germination reduction when applied after 24 h of imbibition than at the beginning. A heat stress of 1 h at 52 °C at the beginning and repeated after 24 h imbibition produced greater germination inhibition of soft seeds than a single 2 h 52 °C treatment at the beginning.

Regional [14C]misonidazole distribution in experimental RT-9 brain tumors

Regional [14C]misonidazole-derived radioactivity (MISO) was measured by quantitative autoradiography in experimental RT-9 brain tumors 0.5, 2, and 4 hr after an i.v. bolus (25 mg) and constant infusion (10 mg/hr). Misonidazole (MISO) concentration in plasma and brain was also measured by high-pressure liquid chromatography; the brain/plasma MISO ratio ranged between 0.5 and 0.7. MISO equivalents were calculated from tissue or plasma 14C radioactivity and [14C]MISO specific activity data. The MISO/MISO equivalents ratio, which represents the nonmetabolized fraction of [14C]MISO, fell gradually in plasma (0.89 at 4 hr) and more rapidly in brain (0.67 at 4 hr) and tumor (0.30 at 4 hr). MISO distributed uniformly throughout the brain at all three time periods. In contrast, MISO distribution in tumor was variable, and tumor concentrations relative to that in brain increased with time. The average tumor/brain MISO ratio was 1.3, 1.7, and 2.6 at 0.5, 2, and 4 hr, respectively, which suggests tumor uptake and binding of MISO or, more likely, MISO-derived 14C-labeled metabolites. In addition, MISO distribution in tumor tissue was strikingly heterogeneous at 4 hr, resulting in an average high/low tumor activity ratio of 4/1 and an average high tumor/brain ratio of 5/1. Tumor regions with high MISO activity correlated in part to viable-appearing cells around necrotic foci.

Regional blood-to-tissue transport in ethylnitrosourea-induced brain tumors

Regional blood-to-tissue transport, expressed as a unidirectional transfer rate constant (K), was measured in experimental brain tumors using alpha-aminoisobutyric acid (AIB) labeled with carbon 14 and quantitative autoradiography. A total of sixteen oligodendrogliomas, four mixed gliomas, three astrocytomas, two diffuse gliomatosis, one anaplastic astrocytoma, one ependymoma and four malignant schwannomas were studied in 9 rats. The mean Ks for all glioma classifications were similar, averaging 2.6 +/- 0.4 (standard error of the mean) ml . kg-1 . min-1, and were only slightly higher than those for nontumorous parietal cortex (2.1 ml . kg-1 . min-1), corpus callosum (0.9 ml . kg-1 . min-1), and a comparable region of brain tissue in the contralateral hemisphere (1.3 ml . kg-1 . min-1). Values of K varied minimally in the intracerebral gliomas and were marginally correlated with tumor cell morphology in only two tumors. In some (but not all) of the larger gliomas, increased vascularity, with or without endothelial proliferation, was associated with a 3- to 15-fold increase in K. Regional K values in malignant schwannomas were highly variable (4 to 207 ml . kg-1 . min-1) and generally were not correlated with specific histological features of the tumor, except in some regions with increased vascularity. Estimates of the average fractional extraction of AIB by the intracranial gliomas and malignant schwannomas were 0.01 and 0.2, respectively; average fractional extractions for nontumorous brain were approximately 0.003.

Regional blood flow in ethylnitrosourea-induced brain tumors

Regional blood flow was measured in experimental brain tumors using iodoantipyrine labeled with carbon 14 and quantitative autoradiography. A total of fifteen oligodendrogliomas, sixteen mixed gliomas, one astrocytoma, one ependymoma, and three malignant schwannomas were studied in 9 rats. The mean tumor blood flows for all glioma classifications were similar, averaging 45 +/- 3 (standard error of the mean) ml . hg-1 . min-1. Flow was fairly uniform within individual oligodendrogliomas and there was no apparent correlation between blood flow and tumor size or location. The mixed gliomas were larger than the oligodendrogliomas and had a wider range of blood flow. Small focal areas of necrosis were observed in 7 mixed gliomas, and low flows were usually measured in these regions; these flows were not always the lowest regional values measured within the mixed gliomas or total group of tumors, however. Small tumor regions with increased vascularity, frequently with endothelial cell proliferation, were observed in oligodendrogliomas and to a greater extent in mixed gliomas; these regions were correlated with small elevations in blood flow (10 to 15 ml . hg-1 . min-1) in comparison with surrounding tumor tissue. Brain adjacent to tumor usually had higher blood flows than that in tumor periphery. Hemispheric differences in blood flow related to the site of primary tumor growth were not observed.

Regional blood-to-tissue transport in RT-9 brain tumors

Regional blood-to-tissue transport, expressed as a unidirectional transfer rate constant (K), was measured in experimental RT-9 brain tumors using 14C-alpha-aminoisobutyric acid (AIB) and quantitative autoradiographic techniques. The magnitude of K depends on the permeability, surface area, and blood flow of the tissue capillaries. The transfer rate constant was variable within tumor tissue (range 0.001 to 0.178 ml/gm/min) and depended on tumor size, location (intraparenchymal, meningeal, or choroid plexus associated), and to a lesser extent on necrosis and cyst formation. Brain adjacent to tumor had higher K values, particularly around larger tumors (0.004 to 0.014 ml/gm/min), than corresponding brain regions in the contralateral hemisphere (0.001 to 0.002 ml/gm/min). Estimates of the fractional extraction of AIB by intraparenchymal tumors were between 0.008 and 0.4 ml/gm/min. Values of fractional extraction in this range indicate that tumor capillaries are not freely permeable to this solute. The values of K measured with AIB in this study, for the most part, approximate the permeability-surface area product of tumor and brain capillaries. The experimental data suggest that the permeability-surface area characteristics of the microvasculature in small RT-9 tumors are similar to those of the host tissue, whereas the microvasculature of larger RT-9 tumors is influenced more by intrinsic tumor factors.

Regional blood flow in RT-9 brain tumors

Regional blood flow (BF) was measured in RT-9 experimental brain tumors using carbon-14 labeled iodoantipyrine, the Kety tissue-exchange equations, and quantitative autoradiographic techniques. Blood flow was variable within tumor tissue, and the range of BF increased with increasing tumor size; the overall range was 6 to 138 ml/100 gm/min and the maximum range within an individual tumor was 55 ml/100 gm/min. In all but one case, mean tumor BF was less than that in the same anatomic region of the contralateral hemisphere (CBA). The magnitude of BF within individual tumor foci generally could be related to tumor size, location (intraparenchymal versus extraparenchymal), and the presence of necrosis or cysts; it was lower in the geometric centers than in the periphery of medium-sized and large tumors. Brain adjacent to tumor had higher BF's than the tumor periphery; generally, the BF in the brain adjacent to the tumor was less than that in the CBA. A global depression of BF was observed within tumor-free cortex and corpus callosum of the hemisphere ipsilateral to tumor implantation and primary growth, suggesting a hemispheric reduction in metabolic and functional activity.

Monoclonal antibody reveals H-2-linked quantitative and qualitative variation in the expression of a Qa-2 region determinant

We have produced a monoclonal antibody, Y-7, that reacts with a Qa-2 region-controlled determinant. Cellular and strain distribution analyses, coupled with quantitative variation in the amount of Y-7 antigen expressed among strains, provide overwhelming evidence that Y-7 reacts with the Qa-2a determinant. The determinant detected by Y-7 is differentially expressed in T and B lymphocytes in a strain specific manner. Y-7 reacts with the majority of T lymphocytes (greater than 95%) and approximately one-half of B lymphocytes in certain strains (+ + strains), and with the majority of T lymphocytes (greater than 95%) and no B lymphocytes in other strains (+ strains). T lymphocytes in + strains express approximately three fold less of the Y-7 determinant than T lymphocytes from + + strains. In addition, we show that the Y-7 determinant is expressed in approximately one-third to one-half of Lyb-3-, 5- B lymphocytes. Possible mechanisms determining quantitative and qualitative variation in the expression of the Y-7 determinant in T and B lymphocytes are discussed.

Steroid therapy in inappropriate secretion of antidiuretic hormone due to malignant thymoma

The authors present the case of a 48-year-old female known to have malignant thymoma with metastases for 6 years and treated continuously for 4 years by corticosteroids with marked regression of tumor. The patient ceased medication on her own accord, and was admitted with extensively enlarged tumor and metastases in association with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). In view of the previous excellent response of the thymoma to corticosteroids, the same treatment was given again with disappearance of the tumor and the features of SIADH. The authors are unaware of previous use of corticosteroids in SIADH as a consequence of their effect on tumor regressions.

Heat-induced changes in the rat parotid gland

Gland size, amylase activity, total proteins and DNA concentrations were measured in parotid gland during chronic heat exposure (34 degrees C). Subcellular fractionation was performed. Exposure to heat resulted in a decrease in gland size and in DNA concentration; amylase activity/100 mg tissue and amylase specific activity to protein concentration ratio increased. Subcellular fractions, except plasma membrane, decreased significantly. Thus, chronic heat exposure slows down the production of gland constituent proteins, whereas acinar function, e.g. the production and storage of exportable proteins, is not disturbed. The reduced gland size is apparently due to hypoplasia.

Interrelationships between heat acclimation and salivary cooling mechanism in conscious rats

1. Adaptation of salivary cooling mechanism during acclimation to heat (34 degrees C) and its role in thermoregulation of the rats was studied on conscious rats with either one submaxillary gland chronically cannulated or both submaxillaries ligated. 2. During heat stress (40 degrees C) acclimated rats showed a decrease both in rectal temperature threshold for salivation (Tre-TS), in salivary flow rate and in Tre (hyperthermic plateau). Animals survived for extended periods and rats with ligated glands survived 40% less than non-ligated rats. 3. For both cannulated and ligated rats short term acclimation (5 days) was the most effective. 4. It is suggested that earlier activation of salivation mechanism is associated with the decreased hyperthermic plateau and that the decreased salivary flow rate allows better control of water balance of the animals. Consequently, survival period during heat stress is extended.

Plasma volume regulation during heat stress: albumin synthesis vs capillary permeability. A comparison between desert and non-desert species

1. Plasma albumin synthesis was measured in rats and sand rats (Psammomys obesus) during heat acclimation (34 degrees C) and following thermal dehydration (37 degrees C) using 3H 1-leucine as a tracer. 2. In rats, heat acclimation resulted in 48% reduction in albumin synthesis. In sand rats synthesis increased by 160%. Both species achieved a new stabilization of the albumin synthetic system on the 5th day of acclimation. 3. Following thermal dehydration albumin synthesis increased in rats and decreased in sand rats. Acclimation did not alter this response. 4. In our dehydrating system plasma volume was maintained via maintenance of adequate albumin mass. In rats, albumin synthesis apparently contributes to this process. In sand rat, vascular permeability rather than albumin synthesis plays this role.

Abnormalities of gastric emptying in obese patients

The pattern of gastric emptying in 15 obese patients and 11 control subjects has been assessed using a double isotope technique for measuring solid and liquid emptying with a scintillation camera. In all studies solid emptying was characterized by a lag period (before food enters the duodenum) followed by linear emptying. Liquid emptying was faster than solid and was non-linear. In obese patients solid emptying was delayed due to prolongation of the lag period, and the duration of the lag period correlated with excess body weight. There was no significant change in liquid emptying in obese patients. In control subjects no relationship between gastric emptying rates and body weight was apparent.

Measurement of gastric emptying after gastric bypass surgery using radionuclides

The pattern of gastric emptying has been assessed after gastric bypass surgery using a double isotope technique for measuring solid and liquid emptying with a scintillation camera. Eleven control subjects and 12 patients, 12 months post-gastric bypass, were studied. Stomal and gastric pouch size were assessed at endoscopy. Solid emptying was slower and liquid emptying was more rapid after gastric bypass surgery. Initial rapid emptying of solid occurred in the 4 patients with the smallest pouch diameters. There was no correlation between stomal size and rates of solid or liquid emptying nor between the weight loss produced by the operation and the rates of solid or liquid emptying, stoma or pouch size.

Effect of modification of fluid intake in the puerperium on serum prolactin levels and lactation

Twenty-one puerperal women were divided into two groups, those with high (4 L/day) and those with low (800 mL/day) fluid intake. Basal and post-suckling serum prolactin levels and the production rate of breast milk were similar in each group. Osmotic influences on prolactin secretion appear to be unimportant in human physiology, and there is no basis for prescribing changes in fluid intake for the control of human lactation.

Clinical evaluation of the sliding compression screw in 121 hip fractures

Between August 1975 and June 1978, the orthopedic residents at the Jacksonville Health Education Program have used the sliding compression screw to treat 135 hip fractures. The 121 of these being reported include 27 subcapital and femoral neck fractures, 88 intertrochanteric fractures, and six subtrochanteric fractures. Patients' ages ranged from 23 to 98 years, with a mean age of 64. Accurate anatomic reduction of the fracture fragments, be it open or closed, and attention to detail in the placement of the compression screws were thought to be major factors favoring a good result. As confidence was gained in the stability of fixation, appropriate patients were allowed postoperative weight-bearing regimes. It was further concluded that the ability of the sliding screw to allow for a "self-seeking equilibrium" of the fracture fragments obviated the need for primary medial displacement in unstable fractures in almost all instances.

Strachan's syndrome 30 years after onset

While a prisoner-of-war in Malaya from 1942-1945, a 29-year-old man developed a painful sensorimotor neuropathy, bilateral central scotomata and sensorineural deafness. Examination 34 years later, after a long period of adequate nutrition, revealed considerable residual deficit. Nerve conduction studies suggested axonal degeneration with prominent collateral reinnervation. This case of Strachan's syndrome is reported to draw attention to the limited functional recovery and to focus attention on this condition at a time when famine conditions are rife in Southeast Asia.

News of risk for early heart disease as a stressful event

Modern prevention includes efforts to reduce the frequency of coronary heart disease by screening populations for certain risk factors, and then advising persons high in risk on how to alter their vulnerability. But what is the effect of telling persons they are at increased risk for such threatening events as heart attacks? Without such information they may not be motivated to change such behavior as cigarette smoking or to comply with blood pressure reducing regimens. With it, worry about their health status may increase. The present study examined such variables in 575 men with no previous symptoms of heart disease who were informed of increased risk and followed for three years. The men were divided at random into two groups of equal size. A Special Intervention group received repeated reminders of risk and procedures for cessation of smoking, reduction of blood pressure, and dietary alteration to lower serum cholesterol. A contrast group received usual medical care, as they saw fit, in response to the news of risk. At yearly intervals, scores on level of subjective distress, avoidance, and coping were obtained. One-third of the men reported intrusive or avoidance experiences one year after receipt of the news of increased risk. The Special Intervention group, with its more frequent reminders, had significantly higher levels of intrusive ideas and feelings about the news of risk than the Usual Care group, and significantly higher levels of coping experiences.

Suppressor cells in vitro: differential effects of indomethacin and related compounds

In vitro immune response systems known to involve suppressor cell regulation were examined for effects produced by the drug indomethacin and other compounds known to inhibit the cyclooxygenase pathway of arachidonic acid metabolism. In all cases tested where suppressor T cell activity is known to be the dominant inhibitory mechanism, suppression was not blocked by drug addition and was sometimes more pronounced. In the cases tested where suppression could be attributed to a non-T cell, most likely a macrophage-like cell (M0), suppression could be abolished by drug treatment. Indomethacin and related compounds may be useful analytical tools for separation of T cell vs. non-T cell mediated suppression.

The effect of intranasal beclomethasone dipropionate on adrenal function

The effect of intranasal beclomethasone dipropionate on adrenal function was assessed in patients with allergic rhinitis. Beclomethasone dipropionate is an effective preparation and therapeutic doses of 400 microgram/day do not cause adrenal suppression after 12 weeks of use.

Plasma water shifts during thermal dehydration

Changes in body water compartments during acute dehydration before and after acclimation to heat and the role of plasma proteins in body fluid dynamics were studied in the rat. Compartment volumes, plasma and interstitial protein concentrations, and colloid osmotic pressures (COP) were measured in anesthetized (with thiopental sodium) and, if necessary, nephrectomized rats. Albumin outfluxes, total protein mass (TPM), and total albumin mass (TAM) were calculated. Nonacclimated rats conserved plasma volume (PV) as long as dehydration did not exceed 15-16% body weight loss (18.6% total body water loss). This was associated with decreased albumin outflux, elevated plasma COP, and reduced subcutaneous COP. When water loss reached 25,5%, PV and extracellular fluid volume decreased by 45 and 34%, respectively. Albumin outflux recovered, TPM and TAM decreased, and plasma COP remained high. In acclimated dehydrated rats PV remained unchanged, albumin outflux decreased, TPM and COP increased, and interstitial COP decreased. Most of the water loss was intracellular in origin. It was concluded that PV changes during dehydration are related to changes in plasma protein distribution. PV conservation rate is different in rats as compared to desert PV conservers.

Impact of Event Scale: a measure of subjective stress

Clinical, field, and experimental studies of response to potentially stressful life events give concordant findings: there is a general human tendency to undergo episodes of intrusive thinking and periods of avoidance. A scale of current subjective distress, related to a specific event, was based on a list of items composed of commonly reported experiences of intrusion and avoidance. Responses of 66 persons admitted to an outpatient clinic for the treatment of stress response syndromes indicated that the scale had a useful degree of significance and homogeneity. Empirical clusters supported the concept of subscores for intrusions and avoidance responses.

Lipid-Modified Antigens

Dodecanoic acid side chains were coupled to the antigen 2,4-dinitrophenyl-bovine serum albumin (DNP-BSA) to make DNP-BSA-lipid. T cells from guinea pigs primed with DNP-BSA-lipid proliferate in vitro when stimulated by most, but not all, DNP-carrier conjugates. Furthermore, DNP-BSA-lipid is a potent stimulator of T cells from DNP-mycobacteria primed animals. This results from its ability to stimulate virtually all DNP-reactive T cells present in such animals, whereas unmodified DNP-BSA stimulates only DNP-BSA reactive clones. When DNP-BSA-lipid was presented to T cells by first absorbing it to peritoneal exudate cells (PEC), it was found that the PEC and the immune T cells had to share I region genes for stimulation to occur. DNP groups can be shown to be present on the surfaces of DNP-BSA-lipid pulsed PEC, as determined by binding of radioactive anti-DNP antibody. Unlabeled anti-DNP will inhibit the binding of labeled anti-DNP to the pulsed PEC, but the presence of the anti-DNP in culture will not prevent stimulation of DNP-reactive T cells by the same pulsed PEC. Taken together, these data suggest that lipid modification of DNP-BSA leads to an increase in its affinity for cell surfaces. Furthermore, they may indicate that this antigen can mimic other DNP-protein antigens by means of a nonspecific association with I region gene products on the surfaces of antigen-presenting cells.

Effects of heat acclimation on the secretory products of the submaxillary gland of the rat. An ultrastructural and biochemical study

Secretory granule area and glycoprotein concentration of the saliva in the submaxillary gland of rats were measured during various stages of acclimation to heat at 34 +/- 1 degrees C. Granule size decreased by 18% during the first five days of heat acclimation (0.025 less than p less than 0.05) after which period it increased to reach 118% of the control levels after 28 days (p less than 0.05). Glycoprotein concentration in the saliva of stimulated glands rose above control levels, reaching a maximum between the 2nd and 5th day of acclimation (p less than 0.05). It was concluded that the initial decrease in granule size reflects a decrease in glycoprotein content following an increase in salivary flow known to occur at high ambient temperatures. The subsequent increase in granule size is considered an adaptation of the gland to continuous stimulation. The rise in salivary glycoprotein concentration suggests increased efficiency of the secretory mechanism.

Polyoma infected cells contain at least three spliced late RNAs

Poly(A)-containing polyoma cytoplasmic RNA was hybridized with linear double-stranded polyoma DNA and RNA displacement loops (R-loops) were formed. The structures visualized in the electron microscope are consistent with the conclusion that there are at least three late polyoma specific RNAs and that the leader sequences at the 5' ends of these viral RNAs are not coded immediately adjacent to the bodies of the RNAs. Measurements carried out on the R-loop structures have provided the locations on the physical map of polyoma DNA, for the bodies and leaders of the RNAs and the length of the bodies, leaders and the corresponding intervening DNA sequences.

Electron microscopic evidence for splicing of SV40 late mRNAs

Poly(A)-containing SV40 cytoplasmic RNA was hybridized with linear double-stranded SV40 DNA and formed RNA displacement loops (R loops). The structures visualized in the electron microscope are consistent with the conclusion that the leader sequences at the 5' ends of the 16S and 19S late mRNAs are not coded immediately adjacent to the main portions of the mRNAs. These data are consistent with either segmentation of the leaders or heterogeneity of their lengths. Measurements carried out on the R loop structures have provided the locations, on the physical map of SV40 DNA, for the bodies and leaders of the 16S and 19S late mRNAs, and the lengths of the bodies, leaders and the corresponding intervening DNA sequences.

Acute dehydration: body water distribution in acclimated and nonacclimated Psammomys obesus

Body water distribution after "acute dehydration" treatment (37 degrees C) was studied in Psammonys obesus before and after acclimation at 34 +/- 1 degrees C for 16-18 days. Determinations of water compartment volumes were performed on anaesthetized (thiopental sodium) nephrectomized animals. Plasma volume (PV) and extracellular volume (ECV) were measured by T-1824 and [14C]inulin, respectively. Total body water was determined after desiccating the animals. Albumin outflux was calculated from the half-life (T1/2) of T-1824 and total plasma albumin mass. Nonacclimated animals conserved PV as long as dehydration did not exceed 10-11% loss of body wt. This conservation was at the expense of ECV and was associated with diminished albumin outflux (T1/2 T-1824 approached infinity). With increased dehydration PV retention failed and a resumption of albumin outflux occurred. Acclimation resulted in diminished albumin outflux in both control and dehydrated animals (T1/2 T-1824 approached infinity). Most of the water lost during dehydration was of intracellular origin. It was concluded that reduction in permeability of the capillary bed during dehydration and acclimatization plays an important role in PV and ECV regulation.

Cellular dynamics of rats' submaxillary gland during heat acclimatization

Male laboratory rats (Rattus norvegicus) ranging between 130 and 160 g were subjected to ambient temperatures of 34.5 degrees C from 0 to 28 days. The submaxillary gland, liver, spleen, and kidney were weighed. The acini size and the mitotic index of the acinar cells after intraperitoneal injection of vinblastine sulfate and colchicine were recorded for the submaxillary and parotid glands. The submaxillary glands showed increased growth rate over the initial 5 days, whereas the growth rate of the other organs decreased. The submaxillary gland enlargement was due to an initial hyperplasia of the acini cells reaching a maximum on the 2nd day. This was followed by hypertrophy of the Acini reaching a maximum on the l0th day. The parotid acini at control values throughout the experiment. It is postulated that the gland enlargement is effected to increase evaporative heat loss during the early stages of acclimatization prior to the lowering of heat production resulting from biochemical adaptation.

Amylase activity, glycoprotein and electrolyte concentration in rat's submaxillary salivary gland during heat acclimation

1. Amylase activity, glycoproteins, Na and K concentrations were measured in submaxillary salivary gland of the rat during heat acclimation (34 degrees C). 2. Acclimation resulted in a decrease in glycoprotein concentration and amylase activity, whereas Na and K concentrations and the Na/K ratio increased. 3. It is suggested that heat acclimation results in an increase in glandular activity leading to increased water secretion and depletion of the glycoprotein store. The decrease in amylase activity is probably due to liver atrophy which occurs during prolonged heat exposure.

Life event questionnaires for measuring presumptive stress

Cumulative stress from the impact of life events has become an important variable in psychosomatic and psychological research. This article provides both short and long life events questionnaires that add to incidence information the remoteness or recency in time of a given experience. In the weight assignment system that leads to a single presumptive stress score, events remote in time have less influence than recent events. The reliability of weight assignment was checked in subject groups that differed by sex, age, and status. Women weighted life events as more stressful than did men; other differences in groups were less important. In spite of the sex differential, review of these data suggests use of the same weight assignments for all subgroups rather than differential weighting by sex and age. Reliability was also checked by test and retest methods in contrast to common sense expectation, a disappointingly low level of reliability was found. The implications for investigative use of life events questionnaires are discussed.