Cellular apoptosis and cell cycle arrest as potential therapeutic targets for eugenol derivatives in Candida auris

Candida auris, the youngest Candida species, is known to cause candidiasis and candidemia in humans and has been related to several hospital outbreaks. Moreover, Candida auris infections are largely resistant to the antifungal drugs currently in clinical use, necessitating the development of novel medications and approaches to treat such infections. Following up on our previous studies that demonstrated eugenol tosylate congeners (ETCs) to have antifungal activity, several ETCs (C1-C6) were synthesized to find a lead molecule with the requisite antifungal activity against C. auris. Preliminary tests, including broth microdilution and the MUSE cell viability assay, identified C5 as the most active derivative, with a MIC value of 0.98 g/mL against all strains tested. Cell count and viability assays further validated the fungicidal activity of C5. Apoptotic indicators, such as phosphatidylserine externalization, DNA fragmentation, mitochondrial depolarization, decreased cytochrome c and oxidase activity and cell death confirmed that C5 caused apoptosis in C. auris isolates. The low cytotoxicity of C5 further confirmed the safety of using this derivative in future studies. To support the conclusions drawn in this investigation, additional in vivo experiments demonstrating the antifungal activity of this lead compound in animal models will be needed.

S9.4b Trimetallic Cu-Zn-Fe nanoparticles induced apoptosis and cell cycle arrest in multidrug-resistant Candida auris S9.4 Free oral presentations (late breaking), September 23, 2022, 4:45 PM - 6:15 PM

Background

Candida species are opportunistic fungus that can cause serious infections, particularly in immunocompromised population. The number of fungal infections has increased steadily with Candida species being responsible for ˃ 70% of these instances, particularly in hospitalized patients with significant underlying conditions. Pharmacological resistance in Candida species and the advent of Candida auris have elevated candidiasis to a major public health concern. Candida auris is an emerging multidrug-resistant fungus that can cause catastrophic bloodstream infections and high fatality rates, particularly in hospitalized patients with major medical issues. Antifungal study of trimetallic nanoparticles (NPs) of various types have been studied as a therapy option for efficient and safe control of candidiasis. These NPs were highlighted for being environmentally friendly and sustainable synthetic preparative possibilities.

Objective

This work aimed to synthesize and characterize novel Cu-Zn-Fe trimetallic NPs and determine their in vitro antifungal activity and mechanism of antifungal action against Candida auris isolates.

Methods

The synthesis and characterization of Cu-Zn-Fe trimetallic NPs was done by standard methods. The antifungal capability of these NPs were determined by calculating minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) following CLSI recommended guidelines. Susceptibility on planktonic cells and biofilms was further confirmed by MuseTM cell count and viability assay and scanning electron microscopy (SEM) respectively. For insight antifungal mechanisms, apoptosis and cell cycle arrest were studied by exploring different apoptotic markers and MuseTM cell analyzer.

Results

Characterizations by Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) determine the successful biosynthesis of Cu-Zn-Fe trimetallic NPs. Susceptibility assay confirmed the fungicidal activity of Cu-Zn-Fe NPs with MIC and MFC values of 12.5 and 25 μg/ml respectively. These results were further confirmed by viability assay reporting the cell viability of 45.5%, 13.5%, and 1.8% when C. auris cells were treated with 1/2 MIC, MIC, and 2MIC respectively. Cell cycle analysis revealed that 91.2% of healthy developing untreated control cells were in G0/G1 phase, whereas 5.2% and 3.7% of cells were in the S phase and G2/M phase, respectively. In contrast, NP-treated cells were observed to be arrested in S phase with 49.3% cells at 2MIC. To study the physiology of cell death caused by NPs, we investigated mitochondrial membrane potential (∆ψm), with live cells having stable (∆ψm) whereas treated cells showed loss of (∆ψm). Another important parameter of apoptosis in yeast cells is the release of cytochrome C from the mitochondria to the cytosol and NP-treated cells resulting in decreased mitochondrial cytochrome C and elevated cytosolic cytochrome C levels. Both results confirmed the potential test NPs in causing apoptotic cell death in C. auris.

Conclusion

The trimetallic (Cu-Zn-Fe) nanoparticles displayed strong antifungal activity against C. auris, with a potential to arrest the cell cycle at S-phase, which could be linked to the DNA damage. Important yeast apoptotic markers suggested that the test NPs have a potential to cause apotosis in C. auris. All these findings suggest the potential of these trimetallic NPs to be taken to the next level of research in the development of novel antifungal medications.

Proteomics Analysis of Escherichia coli Treated with Nanosilver: An Approach to Analyze the Bactericidal Action

Background :

Silver nanoparticles pose high antibacterial properties against multi drugresistant and non-resistant bacteria. However, bacteria acquire resistance against chemically synthesized silver nanoparticles after repeated exposure. Therefore, there is an inevitable need to understand the mechanistic behavior of silver nanoparticles.

Objective:

In this study, we have performed a complete proteomic analysis of Escherichia coli after the treatment with silver nanoparticles to find out the mechanism of bactericidal action of silver nanoparticles (AgNPs).

Methods:

Silver nanoparticles were synthesized using Artemisia annua leaf extract and incubated with Escherichia coli to elucidate the antibacterial assay by determining MIC and the effect on the growth pattern. Further total genome proteins were isolated from control and silver nanoparticles treated bacteria, which were identified by LC MS and Label free quantification analysis technique.

Results::

Total identified proteins were 293, out of which 11 proteins were exclusively present in treated bacteria; these are the proteins mainly expressed in stress conditions. Fold change analysis shows that 65 proteins were upregulated where stress proteins are overexpressed while membrane proteins were downregulated.

Conclusions:

This study reveals that silver nanoparticles inhibit the expression of cellular proteins and cause cell death. Such a study may be helpful in designing drugs against resistant microbes.

Ampicillin Silver Nanoformulations against Multidrug resistant bacteria

The present study reported a single step synthesis of silver nanoparticles using ampicillin (Amp-AgNps), a second-generation β lactam antibiotic to get nanoformulation having dual properties that of antibiotic and silver. The Amp-AgNps was characterized by UV-VIS spectroscopy, TEM, XRD, FTIR and TGA. FTIR and TGA results suggested that amine group of Ampicllin reduce the metalic silver into nano form. These results were further validated by computational molecular dynamics simulation. The antibacterial potential of Amp-AgNps was investigated against sensitive and drug resistant bacteria. MIC of Amp-AgNps against 6 different bacterial strains were in the range of 3–28 µg/ml which is much lower than the MIC of ampicillin (12–720 µg/ml) and chemically synthesized silver nanoparticles (280–640 µg/ml). The repeated exposure to drugs may lead to development of resistance mechanism in bacteria against that drug, so the efficacy of Amp-AgNps after repeated exposure to bacterial strains were also studied. The results indicate that bacterial strains do not show any resistance to these Amp-AgNps even after exposure up to 15 successive cycles. The biocompatibility of these Amp-AgNps was checked against cell lines by using Keratinocytes cell lines (HaCaT).

Removal of toxic contaminants from water by sustainable green synthesised non-toxic silver nanoparticles

The study describes the synthesis of silver nanoparticles using 21 different plant extracts having medicinal properties. Molecular ultraviolet-visible spectroscopy shows that the λ_max of nanoparticles synthesised by different plant extracts varied and ranged between 400 and 468 nm. The ultraviolet results revealed that although synthesis of nanoparticles occurred by all plant extracts successfully, their size varies, this was further confirmed by differential light scattering. The synthesised nanoparticles were investigated for their antimicrobial properties. The most promising silver nanoparticles Ocimum sanctum and Artemisia annua assisted were further characterised using transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). EDX data confirms that synthesised nanoparticles are highly pure. Further these two plant assisted nanoparticles were studied for chemocatalytic and adsorptive properties. The silver nanoparticles from Ocimum sanctum can catalyse the reduction of 4-nitrophenol (63%) within 20 min in the presence of NaBH₄, whereas Artemisia annua assisted silver nanoparticles did not show significant chemocatalytic activity. Both the promising nanoparticles can efficiently adsorb textile dyes from aqueous solutions. These synthesised nanoparticles were also exploited to remove microbial and other contaminants from Yamuna River water. The nanoparticles show excellent antimicrobial properties and can be reused repeatedly.

Preparation and antimicrobial action of three tryptic digested functional molecules of bovine lactoferrin

Lactoferrin is an 80 kDa bilobal, iron binding glycoprotein which is primarily antimicrobial in nature. The hydrolysis of lactoferrin by various proteases in the gut produces several functional fragments of lactoferrin which have varying molecular sizes and properties. Here, bovine lactoferrin has been hydrolyzed by trypsin, the major enzyme present in the gut, to produce three functional molecules of sizes approximately 21 kDa, 38 kDa and 45 kDa. The molecules have been purified using ion exchange and gel filtration chromatography and identified using N-terminal sequencing, which reveals that while the 21 kDa molecule corresponds to the N2 domain (21LF), the 38 kDa represents the whole C-lobe (38LF) and the 45 kDa is a portion of N1 domain of N-lobe attached to the C-lobe (45LF). The iron binding and release properties of 21LF, 38LF and 45LF have been studied and compared. The sequence and structure analysis of the portions of the excision sites of LF from various species have been done. The antibacterial properties of these three molecules against bacterial strains, Streptococcus pyogenes, Escherichia coli, Yersinia enterocolitica and Listeria monocytogenes were investigated. The antifungal action of the molecules was also evaluated against Candida albicans. This is the first report on the antimicrobial actions of the trypsin cleaved functional molecules of lactoferrin from any species.

Fifty-four emergent cricothyroidotomies: are surgeons reluctant teachers?

BACKGROUND

Emergent cricothyroidotomy remains an uncommon, but life-saving, core procedural training requirement for emergency medicine (EM) physician training. We hypothesized that, although most cricothyroidotomies occur in the emergency department (ED), they are rarely performed by EM physicians.

METHODS

We conducted a retrospective analysis of all emergent cricothyroidotomies performed at two large level one trauma centers over 10 years. Operators and assistants for all procedures were identified, as well as mechanism of injury and patient demographics were examined.

RESULTS

Fifty-four cricothyroidotomies were performed. Patients were: mean age of 50, 80% male and 90% blunt trauma. The most common primary operator was a surgeon (n = 47, 87%), followed by an Emergency Medical Services (EMS) provider (n = 6, 11%) and a EM physician (n = 1, 2%). In all cases, except those performed by EMS, the operator or assistant was an attending surgeon. All EMS procedures resulted in serious complications compared to in-hospital procedures (p < 0.0001).

CONCLUSIONS

1. Pre-hospital cricothyroidotomy results in serious complications. 2. Despite the ubiquitous presence of emergency medicine physicians in the ED, all crico-thyroidotomies were performed by a surgeon, which may represent a serious emergency medicine training deficiency.

Status of HIV infection among the pregnant women attending in outpatient department

Human immunodeficiency virus (HIV) infection has been spreading rapidly in the developing countries and vertical transmission also taking place. This study has been done to find out the prevalence of HIV infection among the pregnant women, so that necessity of routine screening test can be identified. It is a cross sectional study. Five hundred two pregnant women were included. Three ml venous blood was taken and then HIV screening test was done by ELISA method. All reactive tests were confirmed by Western blot antibody testing. The positive cases were followed up and necessary treatment was given. Delivery was conducted in this hospital. Baby's blood was tested to see vertical transmission after 18 months. Most of the subject were educated housewife, mean age was 25 years. Six (6%) husband was overseas service holder, 12% were smoker and 1.6% had drug addiction. Eight (8%) subject had previous history of blood transfusion and 49% subject or her husband had history of surgery or got parental therapy. 2% subject gave the history of familial disharmony and 2% had multiple sex partners. HIV infection was found in 2 patients (0.4%). Both of them got infection from their husband. One husband was over seas service holder and another one was injecting drug user. For the prevention of spread, reduction of vertical transmission and providing early management to the positive patient all pregnant women should be screened for HIV routinely.

Characteristics of infertile couples

The objective of the study was to evaluate the sociodemographic characteristics and to find out the causes of infertility among the couple attending out patient department of infertility unit in Bangabandhu Sheikh Mujib Medical University (BSMMU) from January to December 2007. This is a descriptive observational study. Data were analyzed done manually and statistical analysis was calculated by Statistical package for social sciences (SPSS) program. During this period 3184 patients were attended out patient department (OPD) of infertility unit (IU-I & II). Among them primary infertility was present in 1971(61.90%) and secondary infertility in 1213(38%) cases. One thousand four hundred and two (1402) patient's complete data were reviewed from OPD register book of IU-I. The mean duration of the infertility was 4.7(4.52) years. The mean age of female patient was 26.5±5.35 years. The mean age of male patient was 34.56±6.33 years. A positive male factor problem alone was found in 13% couples, female factors in 71.46% couples and unexplained infertility in 15.47% couples. Among the male factor Oligozoospermia (33.33%) was the most common cause of male infertility. Anovulation (52.16%) was the most common cause of female infertility and major cause of anovulation was Polycystic ovary syndrome (PCOS) (29.90%). Fibroid uterus, Bilateral tubal block and Pelvic inflammatory disease (PID) were significantly (p<0.001) higher in secondary infertility. Endometriosis and unexplained infertility were significantly (p<0.001) higher in primary infertility. Distribution of other causes of infertility was same for both primary and secondary infertility.

Ethical awareness in surgical management

Getting information about disease has been suffering, the management needed, procedure and complication of that management, is the right of the patients. Giving that information to the patients is the responsibility of the physician/surgeons. The objective of this study was to assess the existing awareness of the surgeons and female patients regarding ethical issues of medical practices. This observational study was undertaken in the gynecological department of two tertiary hospital of the capital city of Bangladesh. One hundred fifty five patients were interviewed who were underwent surgical management for different gynecological problems. Mean age of the studied population was 41 (SD+/-10) years. All of them were from lower and lower middle economical classes. Sixty three percents (63%) were illiterate. Consent for the surgery was given by the husband in 52% cases, by son in 22% cases, by herself in 1% case and remaining by other relatives. About 50% of the patients did not know the name of their disease, 75% of them never talked with the surgeon. Only in 31% cases surgeon spontaneously explained them about her disease. Most of them had no knowledge about anaesthesia, operating time, need of blood transfusion, operating complications and long-term effects of the surgery they had. The result of this study showed very poor awareness about medical ethics and patient's right.

Laser Doppler imaging determines need for excision and grafting in advance of clinical judgment: a prospective blinded trial

INTRODUCTION

Clinicians' judgment as to which burns require excision and grafting remains one aspect of burn care without objective measurements. This study presents a prospective, blinded trial to assess decision to operate by laser Doppler imaging (numerical criteria) versus the clinical judgment of an experienced burn surgeon.

METHODS

A number of 23 patients were enrolled in this prospective trial and 41 representative wounds of indeterminate depth were selected for observation. Daily determination of need to operate (burn depth) was made by a single burn surgeon. Laser Doppler imager (LDI) scans of the same wounds were simultaneously obtained, and not revealed to the clinician. Data analysis compared quickness of decision to operate by LDI to the clinician's judgment. Concurrence of decisions by either method was compared.

RESULTS

A total of 23 patients and 41 wounds were analyzed. LDI and the surgeon agreed in determination of wound depth 56% of the time (23/41, P=0.031). Biopsy confirmation was obtained for 21 wounds. The surgeon's determination of burn depth was accurate in 71.4% of wounds biopsied (15/21). When the LDI scan median flux indicated need for excision, it was 100% accurate (7/7). When both the surgeon and the LDI were correct in assessing wound depth, LDI would have saved median number of 2 days (minimum=0, maximum=4).

CONCLUSION

LDI allowed for earlier, objective determination of need to operate. Concurrence with clinical judgment in this blinded study was excellent. LDI should be seen as an effective aid to clinical judgment when contemplating excision of burns with indeterminate depth.

Visceral ischemia after cardiopulmonary bypass

The diagnosis and management of gastrointestinal complications associated with cardiopulmonary bypass is often hindered by a complicated clinical picture and equivocal examination. To better define the incidence, risk factors, and mortality, we reviewed the records of all patients undergoing cardiopulmonary bypass from 1988 through 1996. The database for this study comprised 14,521 patients who underwent cardiac surgery. The patients (543) with gastrointestinal complications were identified, and those with major complications (166) were individually reviewed. Major complications included pancreatitis, gastritis, laparotomy, gastric ulcer, cholecystitis, colonic perforation, gastrointestinal bleeding, diverticulitis, bowel obstruction, perforation, and visceral ischemia. Our results were the following. 1) Gastrointestinal complications were noted in 3.7 per cent (543) of patients with major complications occurring in 1.2 per cent. In 166 patients, 187 major complications were noted. 2) Visceral ischemia, an infrequent but usually fatal (71%) complication, occurred in 24 (0.17%). 3) Of the ischemic events, 83 per cent (20 of 24) affected the bowel; with the colon involved 80 per cent of the time (16 of 20). 4) Patients with visceral ischemia were more likely to be female (relative risk 2.1), have longer pump times (92.2 versus 74.2), have cardiac procedures other than coronary artery bypass graft (relative risk 2.6), and have end-stage renal disease (relative risk 16.7). We conclude that, given the incidence and mortality related to visceral ischemia, especially to the colon, patients with risk factors (end-stage renal disease, female sex, non-coronary artery bypass graft, and longer pump times) should undergo routine endoscopic examination of the colon early after bypass and when clinically indicated thereafter.

A placental-derived tissue matrix as a bowel wall substitute in rats: preliminary study

BACKGROUND

Occasionally, conventional closure of an intestinal wall defect (fistula) is not possible. The development of a biologic material that can be used in this setting would solve a significant clinical problem. We hypothesized that a collagen patch (connective tissue matrix [CTM]) designed to allow tissue regeneration was such a material.

METHODS

To test this hypothesis, we performed a laparotomy on 75 male Sprague-Dawley rats (experiment A) and removed 25% of the anterior cecal wall (1 cm in diameter) to compare intestinal wound healing in four situations: (1) control (no repair), (2) fibrin glue repair, (3) primary repair, and (4) repair with CTM (human placental bilayer, types I, III, and IV). Animals were killed at 1, 2, 4, and 6 weeks. Healing was graded by bursting pressure expressed in millimeters of mercury, histologic score (0 to 4), and mortality rates. After this, we used the same protocol to remove 80% of the cecal wall (1.5 x 2.0 cm) in 19 animals (experiment B) to compare (5) fibrin glue repair alone with (6) CTM repair in a situation in which the defect was too large for primary repair.

RESULTS

CTM repair of a lethal cecal wall defect (experiment A) is equivalent to either primary repair or fibrin glue repair. When the defect is too large for primary repair (experiment B), repair with fibrin glue also does not work. However, in this same setting, CTM repair is successful (p < 0.00001).

CONCLUSIONS

Intestinal wall defects not suitable for conventional closure can be repaired successfully with a collagen patch, with histologic characteristics similar to those seen with primary repair.

Does resuscitation produce a reperfusion injury?

Conceptually, shock with resuscitation should produce cellular changes that parallel those observed in a single organ exposed to ischemia with reperfusion, i.e., a transient worsening of the injury pattern after reperfusion with the degree of recovery reflecting the magnitude of the ischemic injury. To test this hypothesis, 74 male Sprague Dawley rats (300-400 g) were randomized into two groups with controls and exposed to 1) hemorrhagic shock (mean arterial pressure < 50 mm Hg) for 2 hours before sacrifice, or 2) shock (2 hours) with reinfusion of shed blood over 1 hour before sacrifice. Mean arterial pressure, blood loss, serum lactate, base excess, and bicarbonate were serially measured to determine the degree of tissue ischemia. At sacrifice, hepatic mitochondrial function was determined by the respiratory control ratio. Our findings were as follows: 1) Hemorrhagic shock produced significant (P < 0.001) tissue ischemia and impairment of mitochondrial function (P < 0.001), 2) resuscitation rapidly corrects the metabolic sequelae of tissue ischemia, and 3) mitochondrial function was unaffected by resuscitation. We conclude that resuscitation rapidly corrects the tissue ischemia associated with hemorrhagic shock, without producing any measurable reperfusion injury at the mitochondrial level.

Portal vein thrombosis in the adult: surgical implications in an era of dynamic imaging

Extrahepatic portal vein thrombosis (EHPVT) is the leading cause of variceal hemorrhage in patients with healthy livers; however, in an era of dynamic imaging, the incidental discovery of EHPVT places a special burden on the surgeon to understand the surgical implications of the disease in this setting. During the period 1989 to 1995, 23 patients (12 males and 11 females) were found to have EHPVT. In 20 (87%), this was an unexpected finding on ultrasound (11 of 23), abdominal CT scan (9 of 23), or both (9 of 23). In two patients, the diagnosis was suspected and confirmed with angiography, whereas in the other, the lesion was discovered at surgery. Only seven (30%) had hemorrhage as a presenting complaint. More typically (61%), abdominal pain alone or pain with sepsis was the indication for evaluation. In 20 patients (87%), there was an identifiable etiology for the EHPVT. A total of 15 operations were performed on 12 patients (52%), in 7 (4, variceal hemorrhage, and 3, bowel ischemia) as a direct consequence of the EHPVT and in five, for conditions not directly related to the EHPVT. Three of the 23 patients (13%) died, two (17%) following surgery and one (9%) from advanced malignant disease. No patients with hemorrhage (seven), even those who required a shunt for decompression (three) or devascularization (one), died. We found that the diagnosis of EHPVT is usually not related to variceal hemorrhage, but rather, abdominal symptoms that serve as an indication for the imaging study. Three subsets of patients emerged: (1) those requiring no surgery (11 patients), (2) those requiring surgery related to hemorrhage (4 patients), and (3) those requiring surgery for conditions other than varices (8 patients). In any of these circumstances, mortality (13%) was related to the underlying disease process rather than EHPVT. Given the earlier recognition of EHPVT, the natural history of the disease has been altered, with outcome reflecting the underlying disease rather than the sequelae of portal hypertension.

A five-year prospective study of the health of children in different ethnic groups, with particular reference to the effect of inbreeding

A 5-year prospective study of 4,934 children of different ethnic groups has demonstrated a 3-fold increase of postneonatal mortality and childhood morbidity in the offspring of consanguineous Pakistani parents. Most of these families contained more than one consanguineous union, resulting in a mean inbreeding coefficient for their children of 0.0686. It is estimated that 60% of the mortality and severe morbidity of this group of children could be eliminated if inbreeding ceased. However consanguinity is much favoured in this minority group, and health education will have to be carefully and sensitively handled.

Why do UK-born Pakistani babies have high perinatal and neonatal mortality rates?

A prospective study of 4934 babies of different ethnic groups has confirmed the high perinatal mortality rate for Pakistanis and has shown that this was not due to a reluctance to terminate a fetus who is known to be seriously malformed. The major cause of early mortality was a high rate of lethal malformations, which occurred in about 1 in 100 Pakistani babies and which accounted for about half of their perinatal mortality. Many of these were autosomal recessive and occurred only in the offspring of consanguineous parents. However, there was also an excess of lethal cardiac malformations which were not associated with parental consanguinity. The remainder of the excess perinatal mortality was probably due to socio-economic factors. These causes are partly amenable to preventive measures, such as the referral of Pakistani women for expert ultrasonography at 18 to 20 weeks of pregnancy.

Race, consanguinity and social features in Birmingham babies: a basis for prospective study

STUDY OBJECTIVE

The aim of the study was to investigate the influence of consanguinity on children's health.

DESIGN

The study is a prospective survey from birth to five years of a cohort of babies born in a multiracial community. This report details the initial findings on consanguinity.

SETTING

Participating families live predominantly in three health districts of Birmingham, and were recruited in three local maternity hospitals.

PARTICIPANTS

Babies of 2432 European mothers, 509 Afro-Caribbean mothers, 625 Indian mothers, 956 Pakistani mothers, and 216 Bangladeshi mothers have been enrolled in the study. Eighty mothers refused to participate.

MEASUREMENTS AND RESULTS

Sociodemographic information was obtained using a structured questionnaire administered at interview. Interview data were supplemented with obstetric information from the medical records. The highest prevalence of parental consanguinity was in Pakistani Muslims (69%), whereas in Muslims from other countries it was 23%, and it was less than 1% in non-Muslims. In the majority of consanguineous Muslim pedigrees the degree of inbreeding was greater than that for first cousin parents.

CONCLUSIONS

This prospective study will allow an assessment to be made about any ill health in childhood arising from parental consanguinity, about whether screening programmes are indicated for particular autosomal recessive diseases, and about whether premarital health education might be beneficial. The study has also documented parental ages in different races and this, together with the levels of parental consanguinity in all races, will be useful in genetic methods for assessing the frequency of recessive genes, the possibility of genetic heterogeneity, and whether or not parental age effect exists for new mutations of specific genetic disorders.