Pathogenicity, morphology, and differentiation of Acanthamoeba

Acanthamoeba keratitis is sight threatening corneal infection caused by pathogenic Acanthamoeba. Previous studies have shown the genotypic differences between pathogenic and non-pathogenic species/strains of Acanthamoeba. In this study, we examined the morphological differences between pathogenic and non-pathogenic species/strains using scanning electron microscopy. Pathogenic Acanthamoeba exhibited higher number of acanthopodia (structures associated with the binding of amoeba to the target cells) as compared to non-pathogens. In addition, interactions of amoeba with the corneal epithelial cells were studied. Only pathogenic amoeba exhibited adhesion to epithelial cells. Further results indicated that phagocytosis occurs in the pathogenic amoeba by the formation of amoebastome (characteristic of amoeba phagocyte). This study showed that Acanthamoeba phagocytosis may be both an efficient means of obtaining nutrients for the amoeba and a significant factor in the pathogenesis of Acanthamoeba infections.

Precurarization and priming: a theoretical analysis of safety and timing

The priming principle suggests that the onset of neuromuscular block may be accelerated if an intubating dose is preceded by a priming dose administered a few minutes earlier. We thought it would be instructive to use a pharmacodynamic/pharmacokinetic model to estimate the risk associated with different priming doses and intervals. In any normal population, there is wide variability in the response to neuromuscular blocking drugs. For most relaxants, the coefficient of variation for the 50% effective dose (ED(50)) approximates 20%-25%. Thus, 1 patient in 50 (-2.05 SD) may have an ED(50) only half of the commonly cited value. By using published pharmacodynamic/pharmacokinetic data, we calculated the effect of administering 10%, 20%, or 30% of the ED(95) on the response of the adductor pollicis muscle in a population normally distributed with respect to drug sensitivity. A dose equivalent to 10% of the ED(95) will rarely produce a measurable neuromuscular effect. As this dose is increased, the potential for clinical weakness rapidly escalates. In 1 in 50 individuals, the usual recommendation of 10% of the intubation dose will produce measurable neuromuscular depression. For vecuronium, the optimal priming interval is 5 min. The safety and dependability of the priming principle is very much subject to the laws of probability.

IMPLICATIONS

When using the priming principle to accelerate the onset of neuromuscular block, the initial dose should not exceed 10% the drug's ED(95). For drugs other than rocuronium, the optimal priming interval is not <5 min.

Acanthamoeba can be differentiated by the polymerase chain reaction and simple plating assays

Acanthamoeba are opportunistic pathogens with invasive and noninvasive species. For clinical purposes it is important to differentiate potentially pathogenic from nonpathogenic isolates. For the rapid and sensitive identification of Acanthamoeba at the genus level, we used a polymerase chain reaction (PCR)-based method which detected as few as five cells. Further, we tested nine isolates of Acanthamoeba for their ability to produce cytopathic effects (CPE) on corneal epithelial cells. On the basis of the results, Acanthamoeba were divided into pathogenic or nonpathogenic groups. However, because CPE assays are not available to every diagnostic laboratory, we developed a simple plating assay based on osmotolerance which correlated well with the CPE assays. Pathogenic Acanthamoeba showed growth on higher osmolarity (agar plates containing one molar mannitol), while growth of nonpathogens was inhibited on these plates. In conclusion, we have developed methods for the rapid identification and differentiation of Acanthamoeba.

Dietary (n-3) polyunsaturated fatty acids exert antihypertensive effects by modulating calcium signaling in T cells of rats

After 10 wk of feeding an experimental diet enriched with (n-3) polyunsaturated fatty acids (PUFA), i.e., eicosapentaenoic acid [EPA, 20:5(n-3)] and [DHA, 22:6(n-3)] (EPAX), blood pressure in spontaneously hypertensive rats (SHR), but not in normotensive Wistar-Kyoto (WKY) rats was reduced relative to rats fed an unsupplemented control diet. Concanavalin A-stimulated T-cell proliferation was diminished in both strains of rats fed the PUFA/EPAX diet. The experimental diet lowered secretion of interleukin-2 in SHR, but not in WKY rats compared with rats fed the control diet. To determine whether there was a defect in calcium homeostasis in T cells during hypertension, we employed the following agents: caffeine, which recruits calcium from the cytosolic Ca(2+)-induced Ca(2+)-release pool; ionomycin, which at low concentrations opens calcium channels; and thapsigargin (TG), which mobilizes [Ca(2+)]i from the endoplasmic reticulum (ER) pool. Caffeine-induced increases in [Ca(2+)]i were not modified by the PUFA/EPAX diet. The ionomycin-induced increases in [Ca(2+)]i in T cells from SHR were greater than in those from WKY rats; consumption of the PUFA/EPAX diet did not modify Ca(2+) influx in cells of either strain. The TG-induced increases in [Ca(2+)]i in T cells from SHR were greater than those in cells from WKY rats. Interestingly, consumption of the experimental diet reduced TG-evoked increases in [Ca(2+)]i in T cells from SHR and increased those in T cells from WKY rats, indicating that the PUFA/EPAX diet could reverse the calcium mobilization from the ER pool in T cells. These results suggest that (n-3) PUFA exert antihypertensive effects and modulate T-cell calcium signaling during hypertension in rats.

Docosahexaenoic acid modulates phorbol ester-induced activation of extracellular signal-regulated kinases 1 and 2 in NIH/3T3 cells

Phosphorylation of extracellular signal-regulated kinases (ERK1/ERK2) has been implicated in cell proliferation of mammalian cells. In the present study, we investigated the role of docosahexaenoic acid (DHA) in the modulation of ERK1/ERK2 phosphorylation, stimulated either with phorbol 12-myristate 13-acetate (PMA) or transforming growth factor-alpha (TGFalpha) in NIH/3T3 cells. We observed that both PMA and TGFalpha induced ERK1/ERK2 phosphorylation within 5 min of stimulation. PMA acts upstream of MEK and via activation of protein kinase C (PKC), as GF109203X, a potent PKC inhibitor, and U0126, a MEK inhibitor, abolished its actions on ERK1/ERK2 phosphorylation. TGFalpha did not act via PKC because GF109203X failed to curtail the degree of ERK1/ERK2 phosphorylation in these cells. DHA alone failed to induce the phosphorylation of these mitogen-activated protein (MAP) kinases; however, this fatty acid significantly curtailed the PMA- but not TGFalpha-induced MAP kinase enzyme activity and phosphorylation in NIH/3T3 cells. Furthermore, we observed that DHA significantly inhibited PMA-induced translocation of two PKC isoforms, PKC alpha and PKC epsilon, from cytosol to plasma membrane. Interestingly, DHA failed to inhibit the PMA-induced translocation PKC delta isoform in these cells. Furthermore, DHA decreased PMA-induced proliferation of NIH/3T3 cells. In this study, we show for the first time that DHA inhibits MAP kinase ERK1/ERK2) activation and proliferation of NIH/3T3 cells via its inhibitory action on PKC alpha and epsilon isoforms.

Yield and costs of screening growth-retarded infants for torch infections

Many infants with intrauterine growth retardation (IUGR) are screened for TORCH infections. The yield and costs of such a practice may not be justifiable. Medical charts of infants with IUGR who had a workup for toxoplasmosis, other (infections), rubella, cytomegalovirus (infection), and herpes (simplex) (titer) (TORCH) infections were reviewed for the presence of clinical findings, laboratory and head ultrasound abnormalities associated with intrauterine infections. Maternal charts and reports of placental pathology were reviewed for identifying maternal illnesses and placental causes associated with IUGR. Seventy-five out of 182 infants (41%) with IUGR had a workup for TORCH infection. Maternal conditions associated with IUGR included: pregnancy-induced hypertension (19%), tobacco use (43%), alcohol abuse (21%), illicit drug use (24%), chronic hypertension, diabetic vasculopathy or collagen vascular disease (12%), and multiple gestation (3%). Placental pathology was available in 53/75 cases. Thirty-six of fifty-three (67%) placentae had abnormalities associated with IUGR: placental infarcts (22 of 36), vasculitis/villitis (15 of 36), placenta previa (1 of 36), abruptio placenta (2 of 36), and velamentous insertion of umbilical cord (1 of 36). Clinical findings among infants included hepatosplenomegaly, cataract or rash (1 of 75), thrombocytopenia and/or neutropenia and/or direct hyperbilirubinemia (11 of 75). Seven out of 75 infants had dysmorphic features. None of the infants (0 of 75) had positive IgM titers for toxoplasma, rubella, cytomegalovirus (CMV), or herpes simplex virus (HSV). No infants (0 of 43) had elevated total IgM titers; one infant (1 of 57) had a positive urine culture for CMV. One infant had evidence of calcifications on head ultrasound and a second infant had hydrocephalus (2 of 43). The costs associated with workup for TORCH infections among 75 infants included: TORCH titers determination: $17,816, total IgM titers: $1318, urine culture for CMV: $5734, and head ultrasound: $28,165. The yield of workup for TORCH infection among infants with IUGR is poor and does not justify the incurred costs.

Proteases as markers for differentiation of pathogenic and nonpathogenic species of Acanthamoeba

Acanthamoeba keratitis is a vision-threatening infection caused by pathogenic species of the genus Acanthamoeba. Although not all Acanthamoeba spp. can cause keratitis, it is important to differentiate pathogenic species and isolates from nonpathogens. Since extracellular proteases may play a role in ocular pathology, we used colorimetric, cytopathic, and zymographic assays to assess extracellular protease activity in pathogenic and nonpathogenic Acanthamoeba. Colorimetric assays, using azo-linked protein as a substrate, showed extracellular protease activity in Acanthamoeba-conditioned medium and differentiated pathogenic and nonpathogenic Acanthamoeba. Monolayers of immortalized corneal epithelial cells in four-well plates were used for cytopathic effect (CPE) assays. Pathogenic Acanthamoeba isolates exhibited marked CPE on immortalized corneal epithelial cells, while nonpathogenic isolates did not exhibit CPE. Protease zymography was performed with Acanthamoeba-conditioned medium as well as with Acanthamoeba- plus epithelial-cell-conditioned medium. The zymographic protease assays showed various banding patterns for different strains of Acanthamoeba. In pathogenic Acanthamoeba isolates, all protease bands were inhibited by phenylmethylsulfonyl fluoride (PMSF), suggesting serine type proteases, while in nonpathogenic strains only partial inhibition was observed by using PMSF. The pathogenic Acanthamoeba strains grown under typical laboratory conditions without epithelial cells exhibited one overexpressed protease band of 107 kDa in common; this protease was not observed in nonpathogenic Acanthamoeba strains. The 107-kDa protease exhibited activity over a pH range of 5 to 9.5.

Isolation of Acanthamoeba-specific antibodies from a bacteriophage display library

Acanthamoeba causes opportunistic eye infections in humans, which can lead to severe keratitis and may ultimately result in blindness. Current methods for identifying this organism rely on culture and microscopy. In this paper, we describe the isolation of antibody fragments that can be used for the unequivocal identification of Acanthamoeba. A bacteriophage antibody display library was used to isolate antibody fragments that bind specifically to Acanthamoeba. Individual clones were studied by enzyme-linked immunosorbent assay, flow cytometry, and immunofluorescence. Four antibody clones that specifically bind to Acanthamoeba spp. were identified.

Influence of nitric oxide synthase II gene disruption on tumor growth and metastasis

The relationship between nitric oxide (NO) synthase II (NOS II) expression and the metastatic ability of tumor cells is inconclusive. We determined the role of host NOS II expression in the growth and metastasis of the B16-BL6 murine melanoma and M5076 murine ovarian sarcoma cell lines. The cells were either s.c. or i.v. injected into syngeneic wild-type (NOS H+/+) and NOS II-null (NOS H-/-) C57BL/6 mice. Both cell lines produced slightly larger s.c. tumors in NOS H-/- mice than in NOS II+/+ mice. However, B16- BL6 cells produced more and larger experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice, whereas M5076 cells produced fewer and smaller experimental lung metastases in NOS II+/+ mice than in NOS II-/- mice. After activation with IFN-gamma and lipopolysaccharide, macrophages isolated from NOS II+/+ C57BL/6 mice produced NO-dependent cytotoxicity in sarcoma cells, whereas macrophages from NOS II-/- C57BL/6 mice did not. In contrast, activated macrophages produced little to no NO-mediated cytotoxicity in melanoma cells. Immunostaining analyses indicated that NOS II expression was apparent in the metastases growing in NOS H+/+ mice and correlated with increased cell proliferation in B16-BL6 lung metastases but with decreased cell proliferation in M5076 liver metastases. Our data suggest that disruption of host NOS II expression enhanced the growth and metastasis of NO-sensitive tumor cells but suppressed the metastasis of NO-resistant tumor cells, proposing that host-derived NO may differentially modulate tumor progression.

Regulation of calcium signalling by docosahexaenoic acid in human T-cells. Implication of CRAC channels

We elucidated the role of docosahexaenoic acid (DHA) on the increases in free intracellular calcium concentrations, [Ca(2+)]i, in human (Jurkat) T-cell lines. DHA evoked an increase in [Ca(2+)]i in a dose-dependent manner in these cells. Anti-CD3 antibody, known to stimulate increases in Ca(2+) from endoplasmic reticulum (ER) via the production of inositol trisphosphate, also evoked increases in [Ca(2+)]i in Jurkat T-cells. We also used thapsigargin which inhibits Ca(2+)-ATPase of the ER and, therefore, increases Ca(2+) in the cytosol. Interestingly, addition of DHA during the thapsigargin-induced peak response exerted an additive effect on the increases in [Ca(2+)]i in human T-cells, indicating that the mechanisms of action of these two agents are different. However, the DHA-induced calcium response was not observed when this agent was added during the anti-CD3-induced calcium peak, though its addition resulted in a prolonged and sustained calcium response as a function of time, suggesting that DHA recruits calcium, in part, from the ER pool and the prolonged response may be due to Ca(2+) influx. In the medium containing 0% Ca(2+), the DHA-evoked response on the increases in [Ca(2+)]i was significantly curtailed as compared to that in 100% Ca(2+) medium, supporting the notion that the response of the DHA is also due, in part, to the opening of calcium channels. Furthermore, preincubation of cells with tyrphostin A9, an inhibitor of Ca(2+) release-activated Ca(2+) (CRAC) channels also significantly curtailed the DHA-induced sustained response on the increases in [Ca(2+)]i in these cells. These results suggest that DHA induces an increase in [Ca(2+)]i via the ER pool and the opening of CRAC channels in human T-cells.

Use of unconventional methods of therapy by cancer patients in Pakistan

Most of the studies related to the use of unconventional methods of therapy by cancer patients have been carried out in the developed countries. This study was conducted to ascertain the frequency, type, and duration of use of unconventional methods of therapy by cancer patients in Pakistan. We also wanted to identify individuals who are most likely to use these methods and to compare the findings with those reported from the developed countries. Between 1 April and 30 May 1994, all patients with histologically proven cancer who visited the oncology unit were interviewed. A printed questionnaire with questions and options was used as an interview guide. Informed consent was obtained. One hundred and ninety-one patients were interviewed, on average, for 25 minutes each. Use of unconventional methods of therapy by cancer patients was widespread (54.5% of all patients). The majority (83.7%) were influenced by family members to use these methods. Traditional herbal medicines (70.2%) and homeopathy (64.4%) were the most commonly employed methods. Thirty-six percent of the users employed these methods before receiving any conventional therapy. Only 15% used these methods after conventional therapeutic options had been exhausted. Patients generally perceived these methods as useful, non-toxic and inexpensive. Age, marital status, socio-economic background, education level and status of underlying neoplasm did not influence the frequency of use of unconventional methods. The use, however, was influenced by gender, family size, and type of underlying malignancy. Patients aware of their diagnosis were less likely to use these methods. This study suggests that use of unconventional methods by cancer patients in Pakistan is widespread. Unlike western countries, these methods are often employed before receiving any conventional therapy. This probably results in a significant delay which can be expected to adversely influence the subsequent disease management and survival. Public education, reduction of cost and easy availability of conventional therapy may be helpful in reducing the use of methods which otherwise may have no proven value.

Methemoglobinemia induced by topical anesthesia: a case report and review

Topical anesthetic drugs are widely used by clinicians during hospital and outpatient procedures and are also available to the public in a variety of over-the-counter preparations. Although generally safe, they may cause potentially life-threatening methemoglobinemia. We describe a patient who developed repeated episodes of severe methemoglobinemia after administration of topical Cetacaine spray (a proprietary mixture of benzocaine, tetracaine, and butamben) employed for pharyngeal anesthesia before endotracheal intubation, and briefly review the etiology and pathophysiology of this disorder. Cautious interpretation of oxyhemoglobin saturation values obtained by pulse oximetry or estimated from arterial blood gas analysis is crucial lest the diagnosis of severe methemoglobinemia and the resulting hypoxemia are overlooked. If necessary, the condition is usually readily corrected by intravenous administration of methylene blue.

Ionotrophic 5-hydroxytryptamine type 3 receptor activates the protein kinase C-dependent phospholipase D pathway in human T-cells

The present study was undertaken to investigate the role of the 5-hydroxytryptamine (5-HT) ionotrophic receptor 5-HT(3) in the activation of human Jurkat T-cells. 5-HT and 2-methyl-5-HT (2Me-5-HT), an agonist of the 5-HT(3) receptor, induced increases in intracellular free Na(+) concentrations, [Na(+)](i), via opening of the ionotrophic receptor in these cells. These two serotonergic (5-hydroxytryptaminergic) agents potentiated phytohaemagglutinin (PHA)-induced T-cell activation. However, they failed to potentiate dioctanoglycerol-plus-ionomycin-stimulated T-cell blastogenesis. Interestingly, an inhibitor of protein kinase C (PKC), GF 109203X, curtailed significantly 5-HT and 2Me-5-HT-potentiated T-cell activation. These results demonstrate that the opening of the 5-HT(3) ionotrophic receptor is implicated in T-cell activation via the PKC pathway. Furthermore, 5-HT and 2Me-5-HT stimulated phospholipase D (PLD) activity, as measured by the production of phosphatidylethanol and phosphatidylbutanol at the expense of phosphatidic acid (PA). GF 109203X significantly curtailed the 5-HT- and 2Me-5-HT-induced PLD activity and T-cell activation. The PLD/PA pathway stimulated by these two serotonergic agents resulted in the production of 1,2-diacylglycerol (DAG) mass in Jurkat T-cells. These results altogether suggest that 5-HT and 2Me-5-HT potentiate T-cell activation via increases in [Na(+)](i) and the activation of the PKC-dependent PLD pathway.

5-HT3 receptor-channels coupled with Na+ influx in human T cells: role in T cell activation

The study was conducted on a human (Jurkat) T cell line, loaded with a Na+ fluorescent probe, SBFI/AM. Serotonin and an agonist of 5-HT3 receptor-channels, 2-methyl-5HT, evoked Na+ influx, whereas the agonists of other serotonergic receptor subtypes, i.e., 5-HT1A and 5-HT1B receptors, failed to induce Na+ influx in these cells. By using 3H-BRL43694, an agonist of 5-HT3 receptor-channels, we characterized 5-HT3 lymphocyte receptors which exhibited a density (Bmax) of 300 +/- 20 fmol/10(6) cells and a Kd of 30 nM in Jurkat T cells. The T-cell 5-HT3 receptor-channel is not regulated either by the protein kinase C or by the free intracellular calcium concentrations as the agents known to activate the PKC and to induce increases in intracellular free calcium concentrations failed to influence the free intracellular Na+ concentrations, [Na+]i, in these cells. Furthermore, an increase in [Na+]i, induced by 2-methyl-5HT, via 5-HT3 receptor-channels seems to stimulate T-cell activation by facilitating the progression of T cells from S to G2/M phase of the cell cycle.

Characterisation of serotonin transport mechanisms in rainbow trout peripheral blood lymphocytes: role in PHA-induced lymphoproliferation

In this study, we investigated the serotonin transport mechanisms in rainbow trout (Oncorhynchus mykiss) peripheral blood Lymphocytes. We have observed that the transport of serotonin is a membrane transport process that have the properties of a secondary active transport system. The binding isotherm of [3H]-paroxetine, a serotonin transport blocker, demonstrated a high-affinity binding site with a positive type of cooperativity, Hill coefficient being higher than unity. Known specific inhibitors of the mammalian serotonin transporter significantly inhibited the uptake process in fish lymphocytes. In order to demonstrate the physiological relevance of the serotonin transporter in T-cell activation, we conducted experiments on lymphocytes activated or not by phytohemagglutinin (PHA), a T-cell mitogen. We have observed that addition of PHA for 24hrs, increased the Vmax but not the Km of this transporter. Serotonin uptake inhibitors diminished the PHA-activated proliferation of fish lymphocytes. The intracellular concentrations of cAMP were found to regulate the serotonin uptake and the PHA-stimulated proliferation as the agents known to augment cAMP stimulated serotonin uptake, and inhibited the lymphoproliferation. Inhibitory effects of increased cAMP on the proliferation were reversed by the addition of the nanomolar concentrations of 8-OH-DPAT, a 5-HT1A receptor agonist which is known to diminish the intracellular cAMP concentrations, suggesting that serotonin also regulates PHA-induced proliferation via 5-HT1A membrane receptors in an autocrine manner. These results all together demonstrate that fish lymphocytes possess an active serotonin transporter that is implicated in the proliferation of these immunocompetent cells.

Body mass index (BMI) in the Saudi population of Gassim

In a total cross-sectional population survey of the Faizia East Primary Health District of Buraidah, Gassim region of Saudi Arabia, 6,044 (2727 male and 3317 females) subjects out of a de facto population of 7695 got their BMI computed because infants and restless or bedridden subjects could not be examined. Mean (+/- SD) and percentiles (25th & 75th) were calculated in the conventional 5-year age cohorts as well as in functional age groups, namely, 0-5, 6-12, 13-49, 50-69 and 70+ years. 5th, 10th, 25th, 50th, 75th, 90th and 95th percentiles were computed only for the functional age groups. In general, the trend was for BMI to increase with age in both genders but the curve pattern showed some plateauing from about the age of 50 with slight decline in later life. Females had significantly higher indices than males, this becoming quite prominent from the 10-14 year age cohort. This difference persisted irrespective of the types of age grouping or residential location. Overall means (+/- SD) were 20.14 +/- 5.98 vs 22.22 +/- 7.21 for males and females respectively; df: 5771; p = 0.0000; 95% CI: -2.43, -1.735. Subjects in the urban living environment had significant higher indices than their rural counterpart: (21.666.92 vs 20.446.33: df: 5771; P = 0.0000; 95% CI: 1.595, -0.840). From the age of 15 about one quarter of females are overweight (BMI at the 75th percentile > 25) and from 30 years the same proportion are frankly obese (BMI > 30). Both systolic and diastolic blood pressure were significantly positively correlated with BMI in both genders: male SBP: r = 0.22, P < 0.0001; male DBP: r = 0.21, P < 0.00001; female DBP: r = 0.18, P < 0.00001.

Studies of preventive nephrology: self-urinalysis as a feasible method for early detection of renal damage

The ever expanding pool of ESRF patients is exerting considerable strain on the health care resources of all nations of the world. Rationing, in one form or the other has therefore become the norm for most countries. Because dialysis prolongs life and is more readily available, and because ethically acceptable donor kidneys remain in short supply, thus limiting the potential of renal transplantation, this rather exasperating situation is bound to continue unless the entry point into the pool can be actively tacked. As part of our initial effort in this direction, we have examined the feasibility of self urinalysis by the general population as an epidemiological tool for detecting evidence of early renal damage by a total population cross-sectional survey of Faizia East Primary Health District (FEPHD) of Buraidah, capital city of the Gassim region of Saudi Arabia. Out of a de facto population of 7,695, 75.37% (5,800) cooperated fully. Majority of those who could not cooperate (881 [11.44%]) were infants and children. A total of 969 subjects (12.59%), mostly males at work, were not available. Only 45 (0.58%) subjects refused to participate. Housewives were significantly more amenable to the organisation of family self-urinalysis than head of the family (92.2% vs 61.4%; chi square = 321.78; df: 3; P < 0.0001). The mean family size was 7.82 (+/- SD: 3.82). Above the age of 4 years, 66.5% of males (2108/3170) as against 81.7% of females (2,641/3232) were able to carry our self-urinalysis. 11.76% of boys and 8.5% of girls below the age of 5 years were able to carry out self-urinalysis. Only 0.05% of male subjects and 0.03% of females failed to interpret colour change for proteinuria correctly. Similar remarkable competence was demonstrated for glycosuria by the population. We conclude that self-urinalysis is quite feasible in the general population, even if illiterates, if young. It can form a sound foundation, if properly harnessed, for a renal registry.

Some aspects of the pattern of systemic hypertension in the adult population of Gassim, Saudi Arabia: age distribution of the subsets of hypertensives

As part of our studies in prevent nephrology, we have recorded causal blood pressure during a total population cross-sectional survey of the Faizia East Primary Health District of Buraidah (FEPHD), capital of Gassim region of Saudi Arabia. Out of 5671 subjects whose blood pressure could be recorded, 2222 were above 19 years of age and constituted our adult population. For this report, hypertension have been defined as equal to and greater than 140/90 mm Hg. Total hypertensive population had been divided into three subsets, based on this basic definition, namely combined systolic and diastlic hypertension (S/DHPN), isolated systolic hypertension (ISHPN) and isolated diastolic hypertension (IDHPN), a format which is not generally clear in previous studies on the subject. The overall prevalence of systemic hypertension was found to be 23.58%, which is lower than the figure of 36% for USA (pre-primary prevention intensive campaign). It is assumed that all the three subsets mentioned above have been used in calculating the latter. Although males tended to be more hypertensive than females (OR = 1.22; Chi Square = 3.89; P = 0.05; C.I.: 1.00 < OR < 1.49), the marginal difference (25.7% vs 22.10%) was largely due to the IDHPN subset (OR = 1.73; Chi Square = 4.48; P = 0.034; C.I.: 1.01 < OR < 2.96). In both the S/DHPN and ISHPN: statistical significance was not achieved. Significantly, ISHPN subset constituted the bulk--56.68%--of the hypertensive population while IDHPN constituted the least--11.64%. When analysed into 10-year-age cohorts, ISHPN showed the steepest rise in prevalence with age. Rather suprisingly, the IDHPN did not rise with advancing age while the S/DHPN slope was in between the two. We are unable to identify this pattern in our literature search on the subject. We cannot assess its significance by this study, but we wonder whether or not it carries any prognostic significance in terms of target organ damage. It is possible that this pattern may be peculiar to the sub-region but it certainly is not spurious and in our view deserves further scrutiny. We wish to suggest that clear definition of the three subsets of hypertensive population should be mandatory when defining prevalence. This may provide some further clues in the prognosis and pathogenesis of target organ damage.

Blood pressure pattern in Saudi population of Gassim

Blood pressure pattern for the Kingdom of Saudi Arabia has not been defined. In a total cross-sectional population survey of the Faizia East Primary Health District of Buraidah, capital of Gassim region, Saudi Arabia, 5671 subjects out of a de facto population of 7695 got their blood pressure recorded. The study district consisted of an urban section and a rural sector. Mean systolic and diastolic blood pressure were computed for the total population in conventional 5-year age cohorts as well as in an arbitrary functional age groups. The curve pattern and trends of the percentiles, were defined. Mean blood pressure (systolic and diastolic) was found to rise with age in both genders (male SBP: r = 0.66, P < 0.000001: female SBP: r = 0.58, P < 0.00001; male DBP: r = 0.53, P < 0.00001; female DBP: r = 0.45, P < 0.00001) and to correlate significantly with BMI. Both systolic and diastolic values were consistently higher in females than males. Overall means (+/- SD) were: for SBP, male 109.9 (+/- 21.57) vs female 114.33 (+/- 21.22) mm Hg; df: 5669: P < 0.00000; CI: -5.5, -2.0; for DBP, male 62.85 (+/- 16.89) vs female 64.67 (+/- 14.99) mm Hg; df: 5669; P < 0.0000; CI: -2.65, -0.989. Proteinuria (macroalbuminuria) was found to correlate positively and very significantly with both systolic and diastolic blood pressure: for SBP: r = 0.074, P < 0.0001; DBP: r = 0.055, P < 0.0001. Perhaps more significantly, in the context of preventive nephrology, is the observation that the intercept of the regression line with blood pressure was below the level conventionally regarded as hypertensive, suggesting that nephron damage may have occurred at this lower level. Overall mean diastolic blood pressure but not systolic was found to be significantly higher in the rural environment than the urban setting: mean rural DBP: 66.43 (+/- 15.699) vs urban: 62.78 (+/- 78); P < 0.00001; rural SBP: 113.71 (+/- 23.95) vs urban: 112.69 (+/- 19.87), P = NS. No discernible effect of consanguinity in marriage on blood pressure could be detected in this study but we believe that further details are required before a definite statement can be made on this important subject. The percentiles presented can only be regarded as foundation figures requiring further validation before they can be useful in determining cut-off levels for hypertension for the Saudi population.

The anti-stress activity of a gem-containing Unani formulation against diverse stressors

Drugs of mineral origin, especially gems, are extensively used in Tibb-e-Unani (Unani Medicine), both as single drugs and as compound formulations. But such drugs have not yet been adequately studied scientifically. Jawahir Mohra (JM) is one such, as yet unstudied, anti-stress Unani preparation, containing a few herbal and animal ingredients also. Therefore in the present study, a modified JM preparation was investigated for its anti-stress activity against physical, chemical and metabolic stimuli. The non-gem complement (NGC) of JM was also studied for action against physical stress. In albino rats stressed by swimming and subsequently tested for motor function by Rota rod (muscle coordination), activity wheel (forced motor activity) and photoactometer (spontaneous motor activity), JM treatment for 7 days produced a striking and significant increase in activity. The NGC also increased the activity significantly which was however less than JM. JM also produced a striking increase in cold swimming endurance and in the latency of post-anoxia convulsions, while pentylentetrazol (PTZ)-induced defecation and urination in an open field arena under continuous stimulation by intense light and sound was significantly decreased. Therefore, the present investigation indicates that the gem-containing Unani compound JM has significant anti-stress activity of a non-specific type against diverse stressors. This could be due to adaptogenic activity of the preparation. The study also shows that the gems in JM contribute significantly to its anti-stress activity.

Contrasting influence of the living environment and gender on systemic hypertension in Saudi population of Gassim, Saudi Arabia

In a cross-sectional total population survey of Faizia East Primary Health District of Buraidah, which is divided into an "urban" and "rural" sections, casual blood pressure was recorded in 5671 subjects. 2222 (910 males) were adults (> 19 years). 3299 (1561 males) were between 3-18 years, making the paediatric/adolescent cohort of the population. The rest were below 3 years and were not included for calculations in this report. For adults, HPN was defined as > or = 140/90 mm Hg and P/A it was > or = 95th percentile for the age cohorts 3-5, 6-9, 10-12, 13-15 and 16-18 years as recommended by The Task Force for Blood Pressure Control in Children (1987). Each of the three subsets of HPN were derived from these basic definitions without modification. In the adults population, overall prevalence (S/DHPN + ISHPN + IDHPN) was 23.58% (524/2222) and gender prevalence was marginal in favour of males (25.71 vs 22.1% for males and females respectively; OR: 1.22, chi square = 3.89; p = 0.05; CI: 1.00 < OR < 1.49). By contrast, overall HPN prevalence in P/A was 10.64% (351/3299) and in all the age cohorts, girls were very significantly more hypertensive than boys. Overall figures were 13.06 vs 7.94% respectively for girls and boys; OR: 0.57; chi square = 22.65; p < 0000019; CI: 0.45 < OR < 0.73. Only in severe HPN (> or = 99th percentile) in 16-18 year age cohort did male preponderance become obvious. When the influence of the living environment was examined, in adult population (urban: 40,001; rural: 1670 subjects), for all age cohorts the rural environment which is largely inhabited by the unsophisticated Bedouins living close to their livestock, significantly predisposed to HPN as compared to the urban setting. Overall figures are 19.95 vs 32.60%, urban vs rural respectively: OR: 0.52; chi square = 40.4; p < 0.000000; CI: 0.42 < OR < 0.64. On the other hand, in the P/A population (2301 urban, 998 rural) for the age cohorts 3-5 and 6-9 years the urban environment significantly predisposed to HPN. At 10-12 years the prevalence was virtually even (12.65 vs 12.71%; OR: 0.99; p: NS). Thereafter, i.e. 13-15, 16-18 year cohorts, the rural environment became more dominant, just like the adult pattern. In other words whatever the factors in the unsophisticated Bedouin "rural" setting which predisposes to HPN does not become operative until after childhood--after 12 years. This contrasting gender and environmental influence in our study population seems unique, being reported for the first time. It may be pointing us in new direction in the elucidation of the pathogenesis of HPN and should deserve further studies.

Doppler echocardiography in cardiac transplant patients: allograft rejection and its relationship to diastolic function

Right ventricular endomyocardial biopsy has been the traditional gold standard for determining cardiac transplant rejection. Although endomyocardial biopsy has proved useful in guiding rejection therapy, this procedure is not without risk. The objective of the present study was to determine whether a noninvasive method for assessing cardiac diastolic function would be of value in predicting biopsy scores. Doppler echocardiographic indices of left ventricular function were compared with biopsy scores in 43 studies from 23 patients (age 50 +/- 8 years). The average time from transplant to echocardiographic study was 1.5 years. Standard clinical indices of diastolic function failed to predict biopsy results. The A-Ar interval, evaluated in 36 studies, was found to significantly decrease (p < 0.003) with increasing biopsy scores. Preliminary results suggest that this echocardiographic parameter may prove useful in predicting biopsy results.

5-Hydroxytryptamine-induced calcium-channel gating in rainbow trout (Oncorhynchus mykiss) peripheral blood lymphocytes

The present study was conducted on peripheral blood lympho-cytes of rainbow trout (Oncorhynchus mykiss) to assess the role of 5-hydroxytryptamine (5-HT; 'serotonin') in calcium signalling. 5-HT-induced increases in intracellular free calcium concentrations, [Ca2+]i, and its action was mediated by 5-HT receptor subtype 3 (5-HT3), but not by 5-HT receptor subtype 1A (5-HT1A) or subtype 2 (5-HT2) in these cells. In Ca2+-containing medium (1 mM CaCl2), 5-HT and 2-methyl-5-HT (5-HT3 receptor agonist) induced increases in [Ca2+]i, whereas in Ca2+-free medium (0 Ca2+, 1 mM EGTA), these two agents failed to evoke increases in [Ca2+]i in these cells, demonstrating that 5-HT mobilizes Ca2+ from the extracellular environment. Furthermore, 5-HT-induced increases in [Ca2+]i are not contributed to by the intracellular endoplasmic reticulum (ER) pool, as thapsigargin, an agent that recruits Ca2+ from ER stores, had additive effects on 5-HT-induced [Ca2+]i responses in fish peripheral lymphocytes. 5-HT-induced increases in [Ca2+]i were mediated by 5-HT3 receptors via gating the calcium through L-type, but not N-type, calcium channels in trout lymphocytes.