Genealogy of principal strains of the yeast genetic stock center.

We have constructed a genealogy of strain S288C, from which many of the mutant and segregant strains currently used in studies on the genetics and molecular biology of Saccharomyces cerevisiae have been derived. We have determined that its six progenitor strains were EM93, EM126, NRRL YB-210 and the three baking strains Yeast Foam, FLD and LK. We have estimated that approximately 88% of the gene pool of S288C is contributed by strain EM93. The principal ancestral genotypes were those of segregant strains EM93-1C and EM93-3B, initially distributed by C. C. Lindegren to several laboratories. We have analyzed an isolate of lyophilized culture of strain EM93 and determined its genotype as MATa/MAT alpha SUC2/SUC2 GAL2/gal2 MAL/MAL mel/mel CUP1/cup1 FLO1/flo1. Strain EM93 is therefore the probable origin of genes SUC2, gal2, CUP1 and flo1 of S288C. We give details of the current availability of several of the progenitor strains and propose that this genealogy should be of assistance in elucidating the origins of several types of genetic and molecular heterogeneities in Saccharomyces.

Hospitalization in peritoneal dialysis patients.

Hospitalization rates are declining more rapidly for peritoneal dialysis (PD) than for hemodialysis patients. This has been postulated to be caused in part by lower peritonitis rates. However, the causes of admission have not been reexamined in the setting of declining rates. We prospectively examined our hospitalization rates, causes of admission, and impact of peritonitis on hospitalization in adult PD patients at a single center over a 4-year period. There were 274 admissions in 168 patient-years for a rate of 1.6 admissions and 13.0 hospital days per patient-year. Rates were greater for men (1.8 v 1.5; P = 0.013), patients with diabetes (2.2 v 1.4, P < 0.001), and those with a higher peritoneal equilibration test result. Creatinine clearance and sex were independent predictors in a multivariate analysis. The most common causes for admission were cardiac disease (14.6%) and peritonitis (13.5%). Peritonitis accounted for 0.21 admissions and 2.0 hospital days per patient-year. Thirty percent of the incident patients were admitted during the first 90 days of dialysis. Admissions for dehydration and glucose abnormalities were more common in the first 90 days. Overall admission rates, as well as admission rates for peritonitis, did not change over time, although hospital days per year decreased. Those admitted for peritonitis had higher peritonitis rates, more time on PD, and were more likely to be black. Eighty-one percent of the admissions for peritonitis were caused by Staphylococcus aureus, Streptococcus spp, or gram-negative/fungal peritonitis. Patients with peritonitis caused by Staphylococcus epidermidis were less likely to be admitted than patients with peritonitis caused by other organisms. To conclude, peritonitis remains a common cause of hospitalization, despite low peritonitis rates. To decrease admissions for peritonitis, attention should be focused on preventing peritonitis caused by organisms other than S epidermidis.

Vitamin K deficiency with hemorrhage after kidney and combined kidney-pancreas transplantation.

Vitamin K deficiency is a common occurrence in the surgical and intensive care unit population, but its incidence in kidney and combined kidney-pancreas allograft recipients has not been described. We report four patients who received cadaveric kidney or combined kidney-pancreas allografts and subsequently developed significant bleeding associated with deficiency of vitamin K. Their coagulopathy promptly resolved with the parenteral administration of vitamin K. Treatment with vitamin K should be considered in kidney or combined kidney-pancreas allograft recipients with a prolonged prothrombin or partial thromboplastin time during the first postoperative week to avoid hemorrhagic complications.

Tolerance of large exchange volumes by peritoneal dialysis patients.

Improving clearances on peritoneal dialysis involves either more exchanges, greater fill volume, or both. An increase in the number of exchanges is inconvenient, resulting in noncompliance. Therefore, the best option is to increase the exchange volumes; however, patients are often reluctant for fear of discomfort. We tested the tolerance of 20 patients blinded to randomly sequenced volumes of 2, 2.5, and 3 L, performed incenter by the dialysis nurse. Each patient underwent one to three exchanges with each volume. At the end of a 4-hour dwell, the patient scored discomfort and estimated the infused volume. Only one study exchange was performed each day; the rest of the time, the patient continued his or her usual prescription. Fifteen of the patients (75%) were not able to identify the exchange volumes. Four of the five patients who determined the correct exchange volume for 67% to 78% of the exchanges (P < 0.04 compared with 33% expected by chance) had a body surface area greater than 1.75 m2. Of 123 exchanges, 84% were associated with no discomfort, 10% with mild discomfort, and 6% with moderate discomfort. Patients were not more likely to have discomfort with 3-L compared with lower fill volumes. Peritoneal clearances of creatinine (6.1 v 6.6 v 7.7 mL/min/1.73 m2) and urea nitrogen (7.3 v 8.6 v 9.5 mL/min) were progressively greater with increasing exchange volumes (P < 0.001). We conclude that the majority of small as well as large patients will tolerate 2.5- and 3-L exchange volumes. If encouraged to do so, many patients could tolerate greater exchange volumes than they are presently using. Exchange volumes should be readily increased as residual renal function declines.

Genotypic characterization of strains of commercial wine yeasts by tetrad analysis.

The objective of this work was to use tetrad analysis to define the genotypes of a number of commercially available wine yeasts for a range of characteristics related to wine making. The levels of sporulation and spore viability of 13 wine yeasts were determined. Sporulation was very low in one strain and varied from low to high in the other 12 strains. Spore viability of these 12 strains varied from 0-95% and this range was comparable to a large sample of naturally-occurring wine strains. Colonies from viable spores, predominantly from 4-spored asci, from 11 strains were characterized for the ten traits: homothallism/heterothallism, fermentation of sucrose, galactose, maltose; growth on glycerol (nonfermentable); slow growth on glucose and glycerol; level of sulfide production; copper resistance; putative presence of a recessive lethal mutation (inviability of at least two spores/tetrad); yellow pigment (in colonies) on sugar media. The number of heterozygosities for these ten characteristics varied from zero to seven in 11 strains, and eight strains were genetically distinct. Another three strains, distinct from these eight strains, were identical for the ten characteristics and also equivalent for the levels of sporulation and spore viability. Although these three strains are marketed under different designations, there is a strong probability that they were derived from a common ancestral strain. The genotypic characterization of these 11 strains constitutes an important foundation for their identification and their use in breeding programs.

Meningococcal septicaemia: treatment with protein C concentrate.

Meningococcal septicaemia is a devastating disease with the potential to develop severe vascular complications. The incidence in Northern Ireland has risen from 27 cases notified in 1992 to 56 notified in 1997. We describe the first use of protein C concentrate in addition to antithrombin III infusion in the management of a life-threatening case of meningococcal septicaemia in the Regional Intensive Care Unit, Royal Group of Hospitals, Belfast, UK. The rationale and the evidence to support the use of protein C concentrate are discussed. Despite the apparent efficacy and safety of this treatment, subsequent cases of meningococcal septicaemia have not received protein C concentrate due to a lack of availability.

The use of subcutaneous erythropoietin in CAPD patients.

There is little data available on the use of erythropoietin in CAPD patients. The available pharmacokinetic and clinical data suggest that a low dose of subcutaneous erythropoietin might be effective. Seven CAPD patients, without active malignancy or infection, self-administered erythropoietin, 2,000 units (a mean of 32 units/kg) subcutaneously, three times a week. The Hct rose from 23% to 31% in a mean treatment time of 7 weeks, or a rate of rise of 1.2% per week. Three of the patients had previously been transfusion dependent. One of these patients and two additional had iron overload (ferritin level greater than 2,000 ng/ml). The drug was paid for by Medicaid (two patients) or private insurance, with the patient paying the uncovered portion, generally 20%. Side effects were minimal. Low dose subcutaneous erythropoietin is effective in CAPD patients.

Pulmonary and renal toxicity of intravenous immunoglobulin.

Three patients treated with intravenous immunoglobulin developed respiratory difficulty and decreased renal function. Previously reported adverse reactions to this class of drugs have included pulmonary toxicity but not, to the best of our knowledge, renal toxicity. Renal dysfunction was mild in one patient but severe in two patients, one of whom required temporary hemodialysis. In all three patients, renal function returned to the pretreatment level after stopping the drug. Urinalysis and urine sodium concentration at the onset of renal failure were consistent with pre renal azotemia although renal biopsy performed later in one patient showed acute tubular necrosis. The exact mechanism of toxicity is unknown, but the fact that all three cases occurred with a particular immunoglobulin preparation would suggest that a contaminant, possibly aggregated IgG might be responsible.

Diabetic nephropathy with concurrent hepatitis C virus infection related membranoproliferative glomerulonephritis.

Diabetes mellitus is often complicated by nephropathy with progression to renal failure. Various forms of glomerulonephritis have been associated with diabetes, sometimes resulting in more rapid deterioration in renal function and occasionally dictating alternative management of these patients in attempts to reverse or contain nephrosis or renal failure. We report the occurrence of Type I membranoproliferative glomerulonephritis (MPGN) with hepatitis C virus (HCV) infection in two patients, in association with diabetic nephropathy. One patient had cryoglobulinemia and cryoglobulin deposits in the kidney. A brief review of the literature on glomerulonephritides occurring in patients with diabetes mellitus is also presented. Clinicians should be aware of the possible occurrence of Type I MPGN and cryoglobulinemia in patients with diabetes mellitus and HCV infection with the appropriate history and physical findings. The therapeutic approach to managing patients with two distinct concurrent lesions remains unresolved.

Iatrogenic hypercalcemia in hemodialysis patients.

Calcium carbonate is frequently used in large doses as a phosphorus binder in hemodialysis patients, which often results in hypercalcemia. In most studies in which calcium carbonate is prescribed to control serum phosphorus levels the patients are not given calcitriol. However, calcitriol may be necessary for suppression of parathyroid hormone. The risk of hypercalcemia when calcium supplements are used in conjunction with calcitriol has not previously been examined in detail. We reviewed the charts of 74 hemodialysis patients (119 patient dialysis years) to determine the relationship of serum calcium to calcitriol, calcium therapy, and PTH levels. Twenty-eight patients (38%) were hypercalcemic at some point. Calcitriol therapy significantly increased the risk of hypercalcemia, independently of calcium therapy (p = 0.032). However, patients on a low dose of calcitriol were more than twice as likely to be hypercalcemic than patients on higher doses. Mean PTH levels were lower in the patients on the lower doses of calcitriol, indicating less severe hyperparathyroid disease. We conclude that hypercalcemia is a common complication in hemodialysis patients on calcitriol and calcium carbonate. Whether lowering the dialysate calcium, as suggested by other investigators, will successfully decrease the risk of hypercalcemia without worsening hyperparathyroidism remains to be determined.

Calcium mass transfer in peritoneal dialysis patients using 2.5 mEq/l calcium dialysate.

Standard peritoneal dialysate has a relatively high calcium concentration of 3.5 mEq/l. Peritoneal dialysis patients thus gain calcium from the dialysate which contributes to the risk of hypercalcemia. Dialysate with 2.5 mEq/l calcium is now available. Theoretically, using dialysate with this calcium content, calcium transfer should be negative (from the patient into the dialysate) when the patient is hypercalcemic, and positive when the patient is normocalcemic or hypercalcemic. Thus, 2.5 mEq/l calcium dialysate may allow larger doses of calcium carbonate to be prescribed. We compared calcium mass transfer (CMT) in 17 stable peritoneal dialysis patients using 3.5 and 2.5 mEq/l calcium dialysate. A solution of 2.05 l, 1.5 g/dl dextrose was dwelled for 4 hours. Calcium was measured in the drained dialysate and serum (total and ionized). Mean CMT was 0.7 +/- 0.5 mEq/exchange using 3.5 mEq/l calcium dialysate and -0.9 +/- 0.9 mEq/exchange using 2.5 mEq/l calcium dialysate (p less than 0.0001). At the time of the CMT studies, the mean serum ionized calcium levels were identical for the two groups (2.6 mEq/l). CMT correlated inversely with serum total calcium, serum ionized calcium, and drained dialysate volume. During hypercalcemia calcium transfer was from the dialysate to the patient when 3.5 mEq/l calcium dialysate was used, but from the patient to the dialysate when 2.5 mEq/l calcium dialysate was used. We conclude that 2.5 mEq/l calcium dialysate is effective in removing calcium and will be helpful in preventing hypercalcemia when large doses of oral calcium compounds are prescribed as a phosphate binder.

An analysis of ten-year trends in infections in adults on continuous ambulatory peritoneal dialysis (CAPD).

Infectious complications are the Achilles heel of CAPD. To determine trends in these events, we analyzed the CAPD related infections of 303 adults on CAPD at a single university center between 1979 and 1989. During this decade the percentage of insulin-dependent diabetics increased from 14% to 39% (p less than 0.005). Peritonitis rates fell from 2.4 episodes/y in 1979 to 0.8 episodes/y in 1989. The proportion of patients with multiple episodes of peritonitis decreased (40% of the patients in 1979-1982 vs 15% in 1983-1989, p = 0.0001) while the proportion of patients with no episodes of peritonitis increased during the same periods (29% vs 49%, p = 0.005). The proportion of peritonitis episodes due to S. aureus rose over the 10-year period (p = 0.005), while those due to S. epidermidis decreased (p less than 0.10). The overall incidence of S. aureus peritonitis remained unchanged. Catheter infection rates initially increased and then fell during the decade; S. aureus remained the predominant cause. The proportion of peritonitis episodes associated with catheter infection rose (13% in 1982 vs 24% in 1989, p = 0.025), and in 1989, 80% of these episodes were caused by S. aureus. Catheter loss was also primarily due to S. aureus infections in 1989 (80%). Infections due to P. aeruginosa were a persistent problem. The proportion of patients transferring to hemodialysis each year paralleled catheter loss rates, which in turn appeared to be more related to catheter infection rates than to peritonitis rates. We conclude that control of S. aureus and P. aeruginosa will be the key to future reductions in the infectious complications of CAPD patients.

T-wave amplitude: relationships to phasic RSA and heart period changes.

T-Wave Amplitude (TWA) has been suggested as an indicator of sympathetic influence on myocardial performance, but critics have argued that TWA is confounded by parasympathetic influence or that it is a non-specific feature of tachycardia. To help clarify the issue, we examined TWA as a function of parasympathetic activity, using cardiac vagal control as measured by high frequency components of heart period variability (respiratory sinus arrhythmia) and of interbeat intervals (IBI), across several stressful tasks. Sixteen male subjects were exposed to Valsalva, Serial Subtraction and Cold-Pressor tasks. After controlling for between-person variance, it was found that RSA did not contribute to TWA and that IBI contributed dependably to TWA only during the Valsalva maneuver, when heart rate was driven very high. In light of these results, we recommend that TWA continue to be considered a candidate indicator of sympathetic influence on myocardial performance, although caution should be used if heart rate is dramatically elevated.

Exit-site location does not influence peritoneal catheter infection rate.

Peritoneal catheter infections are a cause of peritonitis, catheter loss, and permanent transfer of continuous ambulatory peritoneal dialysis (CAPD) patients to hemodialysis. Risk factors for catheter infections have not been delineated. We investigated the location of the peritoneal exit-site location as a risk factor for catheter infection and loss. There was no relationship between catheter infection rates and exit location. Catheters exiting on the beltline had a median infection rate of 0.5 episodes/year, as opposed to 1.2 episodes/year for catheters exiting above the beltline and 0.9 episodes/year for catheters exiting below the beltline (ns). The percentage of catheters that became infected and required removal was the same for catheters exiting above, below, or on the beltline. Although we recommend avoiding the beltline for patient comfort, exit-site location is not an important determinant of infection rates or catheter outcome.

The effect of body weight on CAPD related infections and catheter loss.

CAPD related infections and catheter loss continue to be the major problems facing the peritoneal dialysis patient. Few risk factors for infections and catheter loss have been identified. We hypothesized that overweight and underweight patients may be at increased risk for infections and catheter related problems. We examined the effect of the patient's weight at the start of peritoneal dialysis on the subsequent peritonitis and catheter infection rates, as well as catheter loss. Weight was expressed as a percentage of ideal body weight (IBW). Those patients who were more than 110% of IBW were considered to be overweight, 90 to 110% of IBW normal and less than 90%, underweight. An equivalent percentage of patients were overweight and underweight at the initiation of peritoneal dialysis (55/228, 24% for both groups). Overweight, normal, and underweight patients had peritonitis rates of 1.0, 0.9, and 0.8 episodes/y and catheter infection rates of 1.1, 1.2, and 0.8 episodes/y, respectively. Despite these similar rates, catheter loss due to infectious complications was greatest in the overweight group and least in the underweight group (p less than 0.05). No obvious explanation for the difference in catheter loss rate was found. Neither S. aureus nor P. aeruginosa infections occurred more frequently in the overweight patients. However, S. aureus infections more often led to catheter loss in the overweight patients. Catheter loss due to catheter leaks and failure to drain was similar in the three groups of patients. We conclude that deviation from ideal body weight at the initiation of dialysis is not a risk factor for CAPD related infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Ongoing postdivorce conflict and child disturbance.

This paper reports on the disturbed behavior of children who are subject to entrenched parental disputes over their custody and care after separation and divorce. The 56 children who varied in racial and socioeconomic origin were 4 to 12 years old at entry into the study. They were assessed at two points: at the time of the custody dispute and 2.5 years later. The extent of the child's involvement in the dispute and the amount of role reversal between parent and child predicted total behavior problems and aggression at the time of the legal dispute. These same factors, together with the rate of verbal and physical aggression between parents, predicted total behavior problems, depression, withdrawn/uncommunicative behavior, somatic complaints, and aggression at the 2-year follows-up. There were no main effects for sex and age. However, at the 2-year mark, girls in high-conflict families were more depressed and withdrawn, and older children in high-conflict situations had more somatic complaints and were more aggressive. The findings are considered in the light of a number of etiological mechanisms by which parental conflict affects children.

Relation between mental age and vocabulary development among children with mild mental retardation.

An investigation of the relation between lexical knowledge and mental age (MA) in elementary school-age children with mild mental retardation was conducted. Lexical knowledge was assessed using the Peabody Picture Vocabulary Test-Revised (PPVT-R) and the Boehm Test of Basic Concepts. Items on the PPVT-R focus on labels for objects and events; items on the Boehm focus on relational terms. Mental age was measured via the Columbia Mental Maturity Scale. Results indicated that the relation between lexical knowledge and MA depended upon the nature of the vocabulary test: The correlation between the Boehm and MA was significantly higher than that between the PPVT-R and MA, suggesting that for this population, MA is more strongly related to knowledge of abstract relational terms than to knowledge of labels for objects and events. The latter may be more open to the influence of differential language experience.

Children of Armageddon. Common developmental threats in high-conflict divorcing families.

This article traces how parental vulnerability to the feelings of humiliation and loss (inherent in highly conflicted divorce and custody litigation) distorts parenting capacities and parent-child relationships in distinctive ways, putting children at risk for specific kinds of developmental difficulties. Pre-oedipal children often fail to achieve a complete separation from their primary caretakers. Oedipal children, already struggling with separation issues, manifest sexualized anxiety and discomfort with gender identity. By latency, these children present as fragmented within themselves and in relationships with others. Each stage-specific response is discussed and illustrated. It is argued that mental health and legal professionals can use this in-depth understanding of child responses to help parents reframe their disputing agendas in terms of the child's developmental concerns and preoccupations to produce custody settlements that are more protective of the child's best interests.

An alternate MLU calculation: magnitude and variability of effects.

This study investigated the effect of removing elliptical question responses, imitative utterances, and single-word Yes/No responses before calculating MLU. Forty-seven language samples from preschoolers with and without language impairment were analyzed. Initial MLUs ranged from 2.0 to 6.5 across both groups. The alternate calculation procedures resulted in an average 18% increase in the MLU index, with individual samples increasing as little as 3% or as much as 49%. The magnitude of the effect was primarily related to discourse properties, although in the SLI group there were secondary relationships to language level and proficiency. The observed variation in the discourse properties of language samples makes the alternate MLU index attractive to clinicians and researchers.

Cognition and communication: referential strategies used by preschoolers with specific language impairment.

Ten children with specific language impairment and 10 children with normal language development were asked to describe objects so that a listener could select them. Each trial targeted two out of a group of three toys. The targeted objects were identical or were similar in size or color. Children in the two groups did not differ in referential success, although children in both groups found the size items more difficult. Content analysis of the messages did reveal differences in the referential strategies used most frequently. Children with specific language impairment were more likely to mention the attributes of each object separately, rather than to describe the characteristics common to a pair of objects. Children in both groups talked about separate objects more often when talking about size than about color or object type. Use of this strategy could indicate the effects of attentional capacity on children's solutions to communication tasks.